Diamond cuts explained: A Guide to the Cut Quality of Diamonds (Essential Guide)


Learn What Diamond Cut Actually Means and All About Diamond Cut Grades| 4Cs of Diamond Quality

Understanding Diamond Cut

Diamonds are renowned for their ability to transmit light and sparkle so intensely. We often think of a diamond’s cut as shape (round, heart, oval, marquise, pear), but what diamond cut actually does mean how well a diamond’s facets interact with light. Precise artistry and workmanship are required to fashion a stone so its proportions, symmetry and polish deliver the magnificent return of light only possible in a diamond.

Achieving the best cut for a diamond reflects in the stone’s final beauty and value. And of all the diamond 4Cs, it is the most complex and technically difficult to analyze. To determine the cut grade of the standard round brilliant diamond – the shape that dominates the majority of diamond jewelry – GIA calculates the proportions of those facets that influence the diamond’s face-up appearance. These proportions allow GIA to evaluate what the best cut for a diamond is, by studying how successfully a diamond interacts with light to create desirable visual effects, such as:

  • Brightness: Internal and external white light reflected from a diamond
  • Fire: The scattering of white light into all the colors of the rainbow
  • Scintillation: The amount of sparkle a diamond produces, and the pattern of light and dark areas caused by reflections within the diamond

This short video explains the GIA cut scale and how GIA classifies round brilliant cut diamonds with a cut grade ranging from Excellent to Poor by factoring in a range of parameters including the diamond’s proportions, culet size, girdle thickness, polish and symmetry descriptions.

GIA’s diamond cut grade also takes into account the design and craftsmanship of the diamond, including its weight relative to its diameter, its girdle thickness (which affects its durability), the symmetry of its facet arrangement, and the quality of polish on those facets.

The GIA Diamond Cut Scale for standard round brilliant diamonds in the D-to-Z diamond color range contains 5 grades ranging from Excellent to Poor and is the definitive scale for classifying diamond cuts.

How does pavilion depth affect a diamond’s cut?

The distance from the bottom of the girdle to the culet is the pavilion depth. A pavilion depth that’s too shallow or too deep will allow light to escape from the side of the stone or leak out of the bottom. A well-cut diamond will direct more light through the crown.

Overview, Grades, Quality and Price

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Education » Diamond Cuts Guide: Overview, Grades, Quality and Price

Bottom Line Recommendation

Cut is possibly the most important of the 4Cs. If you ignore it, you can make an enormous mistake. For example, this diamond from James Allen seems like a great find, as it is 5% cheaper than this diamond from James Allen. In reality, the diamond will have no brilliance and is very poor value.

If you’re buying a round diamond, limit your selections to “Excellent” cut diamonds (if graded by GIA) or “Ideal” cut diamonds (if graded by AGS). If you’re buying any other shape diamond, it’s essential that you see a high quality image of the diamond before deciding to buy as fancy shape cut quality cannot be deciphered using certificate stats alone. Because of this, we recommend you stick with Blue Nile or James Allen.

When it comes to round diamonds, despite them all being uniform in shape, the difference between a well cut diamond and a poorly cut diamond is enormous. You can have something like this ridiculously brilliant diamond from James Allen that runs circles around a poor cut like this one from James Allen.   Despite the second one being a higher color grade, the first one is a much prettier diamond.

As always, if you’re unsure about any aspect of the diamond buying process, please feel free to contact us with your questions.

What is a “Diamond Cut”?

Diamond Cut is how well a diamond is cut and polished, including how well-proportioned the stone is, its depth and symmetry. Diamond Cut doesn’t refer to the shape of the diamond, such as an Oval or Pear Shape. Cut quality directly impacts the diamond’s beauty and brilliance. A well cut diamond is luminous and reflects white and colored light back to your eyes. A poorly cut diamond is dull instead of brilliant. 

Differences in Diamond Cut greatly impact beauty, aesthetic appeal and the value of a diamond. It is the most important of the 4Cs.

How GIA grades Diamond Cut Quality for Round diamonds

GIA diamond cutting grades for Round diamonds range from Excellent to Poor. Diamond cut grade is based on a number of factors including symmetry, polish, brilliance and fire. For the most brilliance and beauty, only consider Round Brilliant diamonds with an Excellent cut. Ensure the symmetry and polish of the diamond are either Excellent or Very Good.

The reality is that 55% of all Round diamonds receive an excellent cut grade from the GIA. About 25-30% of these “excellent” diamonds are not recommended. Our consultants review thousands of Excellent cut diamonds and find bad specs (depth, table and angles).

That’s why it’s important to look at the diamond cut grade on the GIA certificate, but to also review the diamond closely yourself or ask an expert. You don’t want to end up paying for an Excellent diamond that’s only mediocre.

Diamond Cut Grade Chart

A professional gemologist at the GIA reviews each diamond under magnification to determine the Cut grade. Here are the GIA diamond cut grades:

Excellent Excellent Cut Diamonds provide the highest level of fire and brilliance. Because almost all of the incoming light is reflected through the table, the diamond radiates with magnificent sparkle.
Very GoodVery Good Cut Diamonds offer exceptional brilliance and fire. A large majority of the entering light reflects through the diamond’s table. To the naked eye, Very Good diamonds provide similar sparkle to those of Excellent grade.
GoodGood Cut Diamonds showcase brilliance and sparkle, with much of the light reflecting through the table to the viewer’s eye. These diamonds provide beauty at a lower price point.
FairFair Cut Diamonds offer little brilliance, as light easily exits through the bottom and sides of the diamond. Diamonds of a Fair Cut may be a satisfactory choice for smaller carats and those acting as side stones.
PoorPoor Cut Diamonds yield nearly no sparkle, brilliance or fire. Entering light escapes from the sides and bottom of the diamond.

The AGS diamond cut grade chart also includes an Ideal grade. Cut quality is graded by the AGS as Ideal, Excellent, Very Good, Good, Fair or Poor. When looking at AGS diamonds, we recommend only considering Ideal cut diamonds for the best quality.

How Cut Grade Affects Price

Diamond cut prices are based on the precision and quality of the cut—primarily its proportions and symmetry. For example, this diamond from Blue Nile is about as perfect a cut as you can get. The depth, table and all other proportions are as exact as can be. Because of that, you are paying a higher price for the diamond, even compared to a typical excellent cut diamond.

If the facets (the glossy flat surfaces of a diamond) are proportional, for instance, they refract and reflect light back to the eye in tremendous fashion. Diamonds that aren’t as precisely cut have facets and pavilions that do not refract and reflect light as spectacularly.

The amount of light return and brilliance found in an exceptionally cut diamond is worth the extra diamond cut price. Without brilliance and fire, a diamond is less than radiant—no matter the Carat weight or table size.

In other words, a diamond’s Cut is the quality that most significantly impacts its beauty. That’s why the higher diamond cut prices are worth every penny—and it’s better to spend more on Cut than on Color or Clarity.

For example, Brian Gavin offers a Signature collection called Hearts & Arrows which includes some of the best Cut diamonds on the market. For instance, this diamond from Brian Gavin has tremendous brilliance at an excellent price point. It would be perfect for a 1 carat diamond engagement ring.

If you’re working within a budget, we recommend forgoing a GIA grade in Color and Clarity to ensure you’re selecting an ideal cut diamond.

Factors affecting Diamond Cut (& Price)

The most important factor in a diamond’s value and price is its Cut quality. Many elements are involved in Cut quality including its proportions, facets, finishing details and ability to reflect light. The better these characterstics are as a whole, the higher the quality of the diamond, and in return, the higher the price. While Color and Clarity play a role in a diamond’s beauty, Cut is the most critical of the 4Cs.

Here are the main factors that affect the price of a diamond:

  • Proportions (table, width, depth)
  • Symmetrical facets (the mirrors, windows and steps of a diamond)
  • Brilliance (brightness of white light reflection)
  • Fire (dispersion of colored light)
  • Scintillation (the flashes of sparkle when light moves)
  • Finishing details (permanent treatment and polishing)

A diamond like this one from Blue Nile seems to be cheap if you are going by the color and clarity. But if you look at the proportions, this diamond is horrifically cut. It is incredibly deep and has a massive table. Under perfect lighting you may see some sparkle. But in real life scenarios this diamond will be devoid of any brilliance.

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Diamond Proportions

To further understand the factors impacting Diamond Cut quality, let’s examine a diamond’s proportions, primarily its table, width and depth. These elements are universally measured and are excellent indicators of a diamond’s cut quality.

Diamond Cut Proportions directly affect a diamond’s ability to reflect light and provide brilliance. Proportions are based on the ratios between size, angle and shape of each diamond facet. Various combinations of these elements impact how the diamond will interact with light, which determines its overall beauty and lasting appeal (as well as its GIA grading).

About Diamond Table

Diamond table % is determined by dividing the width of the table (top surface area) by the width (diameter) of the diamond. For example, if the table facet is 3.5mm wide, and the diamond is 5mm wide, the table % is 70%.

If the table percentage is too large, light won’t reflect off of the diamond’s crown angles and facets. Vibrant reflections of color won’t be seen as the light will escape from the top of the diamond instead of reaching the eye.

If the table percentage is too low, light will remain trapped inside the diamond and be emitted through other parts of the diamond instead of to the eye.

The ideal table % depends heavily on the Diamond Shape. If you’re unsure of an excellent table % for your diamond, please
contact us and we will walk you through the options and factors.

About Diamond Width

A diamond’s width is determined by measuring from one end of its girdle (the diameter at its widest point) to the other end of the girdle.

The width is most important when it comes to determining length to width ratio, which signifies how proportionate the diamond is along with its intended shape (i.e. square vs. rectangular).

Length to width ratio is measured by dividing the length of the diamond by the width. For example, if a diamond has a length of 5mm and a width of 3mm, the length to width ratio is 1.67.

About Diamond Depth

Depth % refers to the height of the diamond, from the culet to the top of the table. Depth is measured in millimeters and percentage. By dividing the depth by the width, the depth % is achieved.

As an example, if a diamond is 4mm in depth and 4.5 mm in width, the depth percentage is 88.8%.

In most cases, a lower depth % of two equal carat diamonds will appear larger due to the increased width. On the other hand, a depth % that is too low can create a darker appearance as it will not reflect light as powerfully.

What happens when a Diamond Cut is too shallow?

When a Diamond Cut is too shallow, light hits the pavillion at a low angle. The light travels through the diamond and exits through the sides, instead of reflecting through the table and to your eyes.

While shallow cut diamonds may seem large based on their table size (they are also called Spready Diamonds), the escape of light at the bottom significantly reduces the diamond’s brilliance, sparkle and fire.

What happens when a Diamond Cut is too deep?

When a diamond is cut too deep, light hits the pavilion at a sharper angle, causing it to immediately reflect to another pavilion. The light is forced to retract and pass through the bottom of the diamond. As this happens, light is dulled and the diamond becomes less vibrant and radiant.

A Diamond Cut that is too deep also tends to look smaller than those of an ideal cut.

What is the best cut for a Diamond?

Simply put, a well cut diamond maximizes the light that strikes each pavilion. Instead of escaping through other parts of the diamond, light reflects back through the crown and table.

When it comes to determining the highest grade possible, GIA uses the term “excellent” while AGS (the inventory of the cut grade) uses the word “ideal.” These cuts are well proportioned with optimal facet angles, allowing the brilliance and fire to pass through the table for all to see.

For these reasons, excellent cuts are more valuable and more luminous. When buyers have a budget, we often advise choosing a smaller, well cut diamond as opposed to a larger carat that is poorly cut.

If you’re unsure of an ideal cut for your diamond, speak to an expert to walk you through the process.

Symmetrical facets

The facets of a diamond are the tiny mirrors that reflect light back to your eyes. Facets surround the diamond’s table. There are facets above the girdle and below the girdle. The pavilion (the part of the diamond below the girdle that reaches to the culet) is also made up of facets. A Round Brilliant diamond is cut with 58 facets total.

The size, placement and symmetry of the facets impact how well the diamond refracts and reflects light. A diamond with unproportioned facets, too many facets or not enough facets, can cause a less than ideal diamond. 


A diamond’s brilliance is the brightness of the white light reflection. When looking at a diamond face-up under light, it should reflect an abundance of white light. A diamond that’s not symmetrical, is cut too deep or too shallow, for example, looks dull instead of brilliant.  


A diamond’s fire is the amount of colored light that reflects off of the table and facets. Diamonds that are well cut not only have brillance but fire too. When looking at the diamond face-up under light—especially daylight—you should see colored light bouncing off of the diamond. If the diamond doesn’t exhibit colored light reflection, the diamond has a low amount of fire.


Scintillation of a diamond refers to the flashes of sparkle when light moves on the diamond’s table and facets. The scattering of light resembles a sparkle and is caused by the light and dark areas on the diamond’s surface.   A diamond with a large amount of scintillation is more desireable. A diamond without much scintillation can appear dull. 

Finishing details

The finishing details are the craftmanship of the diamond and include its permanent treatment and polishing. The polish of a diamond refers to the condition and quality of the facet surfaces. A diamond that is polished well creates a clear mirror for light to reflect off of. A diamond with a poor polish job looks dull because the facets don’t reflect light as vividly. 

Factors for Determining Diamond Cut Quality

Because Diamond Cut is an enormous element in determining the beauty and brilliance of any diamond, there are some complexities. Many factors play a role in how a diamond’s cut quality is determined.

The main factors impacting Diamond Cut Quality are:

  • Proportions: the ratios and sizes of the diamond’s depth, width and table
  • Symmetry: precision of the facets, mirrors, windows and steps
  • Polish: the shine and glow of the diamond surface

When you’re looking to see how well cut a diamond is, take note of how its facets and angles reflect light. Specifically, note how bright and sparkly the light return is when placed under a normal lamp.

You’ll want to gauge the diamond’s fire (the rainbow light of reflection) and its brilliance (colorless light and sparkle of the diamond). Be sure to also watch for any dark spots within the piece.

When a diamond is poorly cut (even if it has a high Color or Clarity grade), light will not reflect as well back to your eyes, making it a duller, more lifeless diamond.

Be sure to review the GIA cut grade on a diamond’s report, which will include ratings of Poor, Good, Very Good or Excellent.

What’s the difference between Diamond Cut and Diamond Shape?

The terms Diamond Cut and Diamond Shape have distinct meanings.

Diamond Shape describes the outline or figure of the diamond. For example, Pear Shaped and Round Brilliant refer to the shape appearance of the diamond.

Cut refers to the facets, symmetry, dimensions and reflective qualities of the diamond. A Heart Shaped Diamond, for instance, may be cut shallow or deep, dull or brilliant. The Heart Shape remains, while the Cut may differ significantly. The finer the cut, the greater the brilliance and fire of the diamond.

Our Recommendations For Buying The Right Diamond

When it comes to selecting an ideal diamond, we recommend a quality Diamond Cut over anything else. For GIA Certified Diamonds, we recommend choosing an Excellent cut grade. For AGS Certified Diamonds, choose an Ideal cut. When we search for a diamond, we filter more heavily on Cut. You can see our parameters by looking at this James Allen diamond search.

For Maximum Brilliance: Consider a Brian Gavin Signature cut. Brian is a leading industry expert in the field of cut optimization. His Signature cuts are on par with the famed Hearts on Fire brand—only far cheaper.

For Round Brilliant Cut Diamonds, don’t give any credence to an online vendor’s cut grade. Only focus on the GIA or AGS cut grade on the certificate.

In addition to reviewing a GIA or other grading report, be sure to look at the diamond yourself or have an expert assist you. Most importantly, ensure the diamond is appealing to you and your personal style and desires.

Our primary focus is making sure your diamond search is easy, simple and accurate. We want you to find the highest quality diamond while staying within your budget.

If you’d like assistance with finding and selecting a diamond, we’ll be happy to filter through the cuts and make recommendations for you.

About the author

Mike learned the diamond business from the ground-up at Leo Schachter Diamonds – one of the world’s top diamond manufacturers. He has been recognized as a diamond industry expert by Time, People, Money, The Daily Mirror, NerdWallet, The Times Herald, Yahoo Finance Australia, The Art of Charm, The Washington Diplomat, The Next Web, and more.

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Wonderful Guide to Diamond Cuts and Shapes

Diamond cut is the single most important factor to consider if you want a sparkly brilliant diamond. Read on.

Diamond Cuts

“I want a dull looking diamond”… said nobody ever.

Of course everyone wants the sparkliest diamond possible. But sadly, this is also where a lot of people make a costly mistake.

Many people think that a more colorless diamond or a more flawless diamond will sparkle more. But in fact, it all comes down to the cut of the diamond.

Cut is the most important factor, and you should never skimp on it.

In this article, we’re going to explain exactly what cut is, why it’s so important, and what you should be looking for.

In this guide:

Diamond Shape vs Cut

© CreditDonkey

The term “cut” is often used to talk about the shape of a diamond (such as “round brilliant cut” or “princess cut”). But shape refers to the form of the diamond, while cut refers to how the diamond’s proportions reflect light.

Each shape also has its own unique shine and affects how sparkly the diamond is. So let’s first briefly go over the 10 most popular diamond shapes.

List of Most Popular Diamond Shapes:

  • Round Brilliant Cut

    The round brilliant cut will always be the most popular and classic shape. The round diamond is beloved for its unmatched brilliance and beauty.

  • Princess Cut

    Edgy yet still delicate, the princess cut is perfect for the trendy girl. It also has intense sparkle and looks good in just about every setting.

  • Cushion Cut

    This “pillow cut” has softly rounded edges for a romantic look. Cushion cut is quickly becoming one of the most popular cuts and looks good in a lot of settings. Though one thing to note is that it’s not as brilliant as other cuts.

  • Oval Cut

    Oval diamonds are great for those who want to stand out a little. They look larger than round diamonds and also make a woman’s finger seem longer and more slender. They’re cut in the same pattern as the round diamond, so they’re very close in terms of brilliance.

  • Marquise Cut

    The marquise cut football-shaped diamond appears the largest of all cuts. The long shape is also flattering on short fingers.

  • Pear Shaped

    Also known as the teardrop diamond, the pear cut is a cross between the round and marquise. It’s a unique, beautiful cut that looks especially good in a halo setting.

  • Emerald Cut

    The ultimate vintage cut, an emerald diamond exudes old-world glamour. Unlike the multi-faceted brilliant cuts, this step-cut diamond isn’t known for sparkle, and should be enjoyed for its luster and clarity instead.

  • Asscher Cut

    The asscher diamond can be seen as a 21st-century update to the emerald. It’s square-shaped and more sparkly. Ideal for the girl with vintage tastes, but also with modern flair.

  • Radiant Cut

    Combining the best of a few cuts, the radiant diamond exhibits fierce sparkle. Because of its cropped corners, it’s also a good choice for active girls who prefer a square or rectangular shaped diamond.

  • Heart Shaped

    Who else but for the hardcore romantics? A heart shaped diamond is best set as a solitaire to speak for itself.

Learn more about the different diamond shapes. We go through the most popular shapes, including the pros and cons of each.

You may also hear “cut” in terms of the cut technique. This means the way the diamond is cut to form facet (or surfaces) patterns. Here are some popular terms you may come across:

  • Brilliant cut: This pattern is cut in a way for the maximum light return through the top of the diamond. Usually, this refers to the classic round diamond. The modern brilliant cut has 57 facets.
  • Modified brilliant cut: This refers to other shapes cut in the same pattern as the round brilliant cut. The modified brilliant family includes: oval, pear, marquise, and heart. Since they’re in the same pattern as round, they’re very close in terms of brilliance.
  • Step cut: This type of cut has “steps” running down the sides and on the top. There’s a large open window on top that’s like peering into a hall of mirrors. This type of cut is not very sparkly, and shows off the beautiful quality of the diamond instead. Emerald and asscher diamonds are both in the step cut family.
  • Mixed cut: In this cut, usually, the top (crown) is cut in the pattern of a brilliant cut, and the bottom (pavilion) is cut in the pattern of a step cut. This gives the diamond sparkle while keeping more weight. Princess, cushion and radiant diamonds are mixed cuts.
  • Rose cut: This is a vintage cut with a flat bottom and a domed top. Face up, it looks like a rose bud. While a beautiful name, the rose cut is not known for brilliance. It was developed before modern cutting techniques.

What Is Cut and Why It’s So Important

Cut is one of the 4Cs of a diamond (cut, carat, color, and clarity). These characteristics determine the quality and value of a diamond. Cut makes the biggest impact on the brilliance and beauty of a diamond.

Related: Learn more about the 4Cs. Find out which diamond characteristics are more important and which you can save some money on.

A rough diamond has no shine. Instead, a diamond sparkles so much because of how it’s cut and how light bounces off each angle and facet. Cut refers to the proportions, symmetry, and polish of the diamond. Together, these affect the visual beauty and how much sparkle we see.

In a well-cut diamond, the light will enter from the top, bounce around, and exit again through the top. This returns almost all light into the viewer’s eyes.

On the other hand, a poorly cut diamond will leak light and therefore seem dull.

Diamond Cut Scale © CreditDonkey

A perfectly-cut diamond will have the most ideal proportions (explained later) and excellent symmetry and polish. Each facet is precisely cut so that the light can reflect back to the viewer in just the right way. This means that the diamond will give off the most brilliance, fire, and scintillation.

Unlike color or clarity (which are natural qualities of a diamond), cut is solely based on the craftsmanship of the cutter.

Examples of How Cut Quality Affects Beauty

Below, we have examples of diamonds of different cut qualities (Good / Very Good / Ideal / TrueHearts) on James Allen. You can easily see that the better the cut, the more beautiful the diamond.

Even the most colorless and flawless diamond will be wasted if the cut is poor.

For example, take a look at the pictures below. Which diamond looks better to you?

The diamond on the left is completely colorless (D) and virtually flawless (VVSI). And yet because of the poor cut, it doesn’t look good. The diamond on the right is near colorless (G) and very slightly included (VS2). But because of the excellent cut, it’s a beautiful diamond that will sparkle.

For almost $4,000 less, it’s clear which is the better choice.

And another huge plus: a well-cut diamond is literally so sparkly that it hides inclusions and masks slight color. This means you can save money in color and clarity. This article offers a detailed guide to buying a diamond for the best value.

Tip: Only round and princess shaped diamonds are given a cut grade by the GIA and AGS. And if you ask us, even though they call it “good cut,” it is not good enough for your engagement ring. Aim for a cut of Excellent from GIA and AGS. We’ll explain later in this article.

Search for Ideal Cut Diamonds

An Ideal Cut Makes the Diamond Appear Larger

Or rather… an ideal cut makes the diamond the right size for its carat weight.

Because you see, diamond cutters have a lot of pressure to cut stones as large as possible from a rough. Especially to hit a desirable carat weight (such as 1 carat) in order to fetch the highest price. Sadly, this means that a lot of diamonds are cut for maximum weight instead of for maximum brilliance.

© CreditDonkey

The diagram above shows how a rough stone can be cut in two ways. It can either yield a deep diamond with a heavier carat weight, or a smaller ideal-cut diamond. Can you see how much of the weight is wasted on the deep cut? And yet, both diamonds are the exact same size face-up.

Let’s look at this example:

  • The diamond on the left is 1.00 carat and has a “good” cut. The surface area is 6.23×6.26mm.
  • The diamond on the right weighs in at 0.92 carats and has an “excellent” cut. The surface area is 6.23×6.2mm.

In other words, the two diamonds have the same surface area. Face-up, they are both look the same size. But because of the poorer cut of the first one, about 10% of the carat weight is wasted on the deep cut. It hits the coveted 1-carat mark, but it’s not going to sparkle as much.

For about $500 cheaper, the smaller diamond on the right is a much better buy.

This is why you should not place so much importance on carat weight. What’s the use of having weight where you can’t even see it? And no one wants a lackluster diamond.

Search for Ideal Cut Diamonds

How Diamond Cut is Graded

Diamond cut is graded based on their light performance and optical beauty. But not all jewelers and labs have the same standards. To make sure your diamond is graded accurately, we only recommend diamonds with GIA or AGS certificates. These are the two largest labs with the most consistent, high standards.

Cut is given the following grades by GIA/AGS:

Ideal (0)
ExcellentExcellent (1)
Very GoodVery Good (2)
GoodGood (3 – 4)
FairFair (5 – 7)
PoorPoor (8 – 10)

Note: Only round and princess cut diamonds are given a cut grade by GIA and AGS.

AGS tends to have a more rigorous cut grading system. AGS’s top grade of 0 Ideal has higher standards than GIA’s top grade of Excellent.

When giving diamonds a cut grade, the lab will take scans and analyze many factors:

  • The overall proportion and symmetry of the diamond’s cut pattern
  • The polish on the surface of the diamond
  • The diamond’s weight compared to its face-up size
  • The light performance of the diamond (how it reflects light, if it has dark areas, etc.)
  • The white light and rainbow light reflections

Super ideal and Excellent diamonds will reflect almost all the light back (meaning super sparkly), while Poor diamonds will leak a lot of light. In our opinion, even if a diamond is graded “Good”, it’s not good enough for engagement rings.

We recommend a cut grade of Excellent if you can, or at the minimum, a Very Good if you truly can’t afford it. Don’t go down any more. It’s better to go down in color or clarity if you’re on a budget.

What about diamond earrings? Diamond stud earrings aren’t going to be as closely scrutinized as an engagement ring. Nobody is going to get so up close to your earlobes. So you can pick diamonds lower in color (J+) and clarity (11+). However, people will notice how big and sparkly they are. So go for a cut of Very Good at the very least.

Ideal Proportions for Maximum Bling

You can either trust the GIA or AGS grading reports. Or you can do a bit of homework yourself by looking at the proportions.

© CreditDonkey

For reference only – here are proportions you should look for in a well-cut diamond.

Table Percentage53% – 58%
Depth Percentage59% – 62%
Crown Angle34 – 35.5 degrees
Pavilion Angle40.6 – 41 degrees
Pavilion Depth42.5 – 43.5%
Girdle ThicknessThin – Slightly Thick
SymmetryVery Good – Excellent
PolishVery Good – Excellent

All these measurements and angles work together to reflect light back into the viewer’s eyes. It’s just physics.

Now, let’s explain the terms:

  • Crown is the top part of the diamond (the part you see).
  • Pavilion is the bottom part of the diamond (the part you don’t see).
  • Table is the flat surface on top of the diamond. The table percentage is the width of this compared to the entire width.
  • Depth is the height of the diamond from top to bottom. The depth percentage is the height compared to the total width (or diameter). A small depth percentage means the diamond is too shallow, while one that’s too big means the diamond is too deep.
  • Pavilion depth is the height of the pavilion (the bottom part) compared to the total width. Again, too low means the diamond is too shallow, and too high means it’s too deep.
  • Culet is the very bottom tip of the diamond. In a well-cut diamond, it should be a perfect point. Sometimes, this is cut into a very small facet. If it’s too large, then light can pass through it. Or it can be seen from the top and look like a flaw.
  • Girdle is the edge that divides the crown and the pavilion. You don’t want it to be too thin because it’ll be easy to chip. You also don’t want it to be too thick because then weight is added where you can’t see it.
  • Symmetry is basically what it sounds like. Everything should be nice and centered and all facets should be the same and in line. This affects light performance, because if a facet is slightly out of place, it can completely misdirect the light. You’ll want a grade of “very good” or “excellent”.
  • Polish refers to the smoothness and shine of the finished surface. You also want a grade of “very good” or “excellent” for this.

Tip: A facet is one tiny surface of the diamond. So a round diamond with 57 facets have 57 “surfaces” total. Think of each one like a tiny mirror. Diamonds are so sparkly because light enters in and bounces around the facets and exits again through the top.

Using Idealscope to Understand Light Performance

Yes, you can use dimension charts to gauge how well cut a diamond is. But the best way is to study Idealscope and/or ASET images.

Both Idealscope and ASET measure light performance by showing you areas of light leakage and light return. We’ll give you a brief lesson on how to evaluate these images.

Here are Idealscope and ASET images of a diamond that shows a bit of light leakage (images from Whiteflash diamonds):

And compared to a super ideal diamond with perfect light performance:

Tip: Keep in mind that Whiteflash has super strict cut requirements. Even their lowest quality line is still better than a lot of jewelers. We’re not saying the first diamond is poor quality at all. This is just an example to show what light leakage looks like.

In a nutshell, here’s what you’re looking at:

For the Idealscope images (on left), the amount of light return is shown in red. You can see that the center of the first diamond has a lot of white, which means light leakage. The super ideal cut diamond, on the other hand, is all red. This means that all light is returned to the viewer (i.e., super sparkly).

The ASET image (on right) pretty much shows the same thing. It provides more information than the Idealscope. But for the normal person, you only need to know that you want as much red and green as possible. In the case of the first diamond, light leakage is represented by the dark areas.

These images truly reveal everything. So don’t trust a jeweler’s word unless you can see proof.

Tip: Unfortunately, most diamond retailers do not provide this light performance data. If you’re buying online, always request Idealscope and/or ASET images. And if you’re shopping in person, make sure the jeweler will let you examine the diamond with an Idealscope.

Price Differences Between Cut Grades

Price-wise, here’s an example of what the differences between cut grades look like. All diamonds are 1 carat, have color of H and clarity of VS2.

It is quite a jump to the “excellent” cut (and even more to super ideal – what James Allen calls “TrueHearts”). But in our opinion, this extra money is well worth it, as the difference in quality is very visible. If you’re working on a tight budget, go down grades in the other areas before you go down in cut.

Where to Find Ideal Cut Diamonds

A high-quality cut is the hardest of the 4C’s to find. Only about 3% of the world’s diamonds are ideal cut, simply because most diamonds are not cut for beauty and maximum brilliance.

If you’re buying from a jeweler, be very careful if they claim the diamond is ideal-cut. Only trust it if the diamond has been certified by GIA or AGS. And if the jeweler refuses to show you Idealscope or ASET images, then stay far away!

If you’re shopping online, we’ve got our most trusted suggestions for where to shop for ideal cut diamonds.

  • Whiteflash A CUT ABOVE®: Whiteflash is our favorite diamond retailer for high-quality cut. They have one of the largest inventory of ideal cut diamonds in the world. They are especially known for their signature A CUT ABOVE® super-ideal cut diamonds. These are their hearts & arrows (H&A) diamonds that have received perfect ratings in light performance, symmetry, and polish.

    Whiteflash also offers a great Expert Selection. This contains diamonds that just didn’t quite make it into the A CUT ABOVE® line. This is where you can find a high-quality diamond for a more budget-friendly price.

    Each of Whiteflash’s in-house diamonds comes with light performance and H&A imagery upfront. So you can be confident in your purchase.

  • James Allen True Hearts: This is James Allen’s line of hearts & arrows diamonds. The selection is somewhat limited, but their user-friendly website is unmatched when it comes to diamond shopping online. Their True Hearts diamonds all come with Idealscope and H&A imagining.

    Or if you’ve got your eye on another diamond, you can request up to 3 Idealscope images for free. This way, you can compare and see which has the best light performance.

  • Brian Gavin: All Brian Gavin diamonds are cut to the most exacting standards for the best light performance. It offers super ideal diamonds in round, princess, and cushion cuts. The unique thing about Brian Gavin is that it has several product lines to suit every budget. For example, it offers diamonds with fluorescence or warm toned diamonds. This allows you to buy a high-quality diamond on a smaller budget.

Bottom Line

The cut of the diamond is the single factor that makes the largest impact on appearance. Even the most colorless and flawless diamond will look dull if the cut is poor.

So we highly suggest that you prioritize cut above all else – even above carat weight. Don’t try to skimp here. Instead, save your money in the color and clarity areas, as an excellent cut will mask color and hide flaws. And everyone wants their diamond to sparkle.

Note: This website is made possible through financial relationships with some of the products and services mentioned on this site. We may receive compensation if you shop through links in our content. You do not have to use our links, but you help support CreditDonkey if you do.

Diamond Cut, Sparkle & Brilliance | Diamond Education

Diamonds are cut to maximize the sparkle, fire, brilliance and overall visual beauty of a diamond. The cut is a measure of light performance as light hits a diamond. Before a diamond is cut and polished, it is known as a rough diamond. The skin of the rough diamond is opaque and often difficult to see through. Rough diamonds have little to no sparkle. This is because they lack facets or faces that bounce and reflect light. Diamonds sparkle is a result of light performance. As light hits a diamond, it penetrates the diamond, bounces around and reflects within the diamond and ultimately returns light to your eye. That is the sparkle that you see.The cutting of a diamond directly impacts the amount of light performance achieved. The angles, locations, sizes and shapes of facets will determine the diamond sparkle.

Cut Scale: The Factors

Once a diamond has been cut and polished, it’s cut can be graded. GIA grades cut base precisely measuring the angles and sizes of the facets of a diamond. These include the diamond’s Table, Depth, Girdle, Pavilion, Crown and Culet. Polish and Symmetry can also place a small role. All these factors come together to determine the cut grade of the diamond. Each diamond shape and size has an ideal cut proportion. If you’re looking for an ideally cut diamond, simply ask one of gemologists and they can point out a few diamond options that have ideal proportions.

Finish: Polish, Symmetry and Facets

Other factors that affect the cut grade are polish, symmetry and faceting. Diamonds are typically cut in two ways: step cuts and brilliant cuts.

Step cuts, such as Emerald cut diamonds and Asscher cut diamonds, have sparkle or fire. They have facets that look like a staircase and are a bit simpler in presentation. They are considered very elegant and maximize the diamond’s scintillation. These cuts are elegant but because they have fewer facets do not reflect light as much as brilliant cut diamonds. While both diamonds have unique beauty, it is important to consider which type of diamond sparkle you want while picking a diamond cut.

Brilliant cuts, most commonly Round cut diamonds or Princess cut diamonds, have maximum diamond sparkle. They possess more facets than step cuts and the facets are triangular and kite-shaped. Brilliant cuts have a high degree of diamond sparkle and maximum the fire and scintillation of a diamond.

Moreover, polish and symmetry are a result of the manufacturing process. The polish of a diamond is how cleanly smooth the facet surfaces are. If small striated polish lines remain, it may affect light performance and therefore, diamond cut. The other attribute is symmetry. Symmetry is simply the pattern and evenness of the size, shape and location of facets. If the location of a facet is incorrect, the performance of light and therefore the cut grade can be affected. For example, an off center table facet may reduce diamond sparkle.

Pricing Effect

Like the other diamond C’s, Cut grade can have substantial implications on pricing. Today, we see the highest number of Excellent cut or perfectly cut diamonds. The improvement of diamond manufacturing technology allows diamantaires to be more precise in cutting practices. With round cut diamonds, an Excellent cut can have a 5%-10% premium over the next grade, Very Good cut. The same applies from Very Good to Good.
Fancy shaped diamonds (shapes other than Round cut) do not have GIA assigned cut grades. This is because with fancy shapes, diamonds can have a variety of shapes and lengths/widths all the while still maximizing brilliance and sparkle. With Clarity factors in a variety of diamond attributes to assign its own grading standards to fancy shapes.

Selecting Cut Grade

Cut is often consider the most important of the 4 C’s of diamonds (carat is more of a preference, not an art or science). When selecting a diamond, it will certainly important to ensure light is not lost. Excellent cuts are most premium and Very Good cuts offer more value. The differences in sparkle are quite subtle, but they are noticeable when compared side by side. We recommend maximizing on the Cut grade, if possible.

Fancy shapes have less restrictions because beauty is in the eye of the beholder. Still, you can often safely go a grade lower with non round diamond shapes. Excellent cut fancy shapes are fairly rare.

In the end, it’s your decision and you must remember there are plenty of other factors that influence a diamond. You must choose which factors/attributes matter most to you.

Shop by Cut

Diamond Brilliance: What Makes Sparkle

When diamonds are found in the earth whether as alluvial deposits or within rough, they are certainly not the well-cut shining gems that we see in jewelry. When found in the earth, diamonds actually have an opaque and rough skin on top. When polishing and cutting a diamond, this exterior skin is removed. In addition two important factors are considered. First is the refractive index of the diamond which is responsible for the brilliance of the diamond. And second is the dispersive power of the diamond which allows it’s ability to split white light and reflect back additional colors. The term scintillation brilliance is applied to the number and arrangement of light reflections from the internal facets that shows of sparkle as the wearer of the diamond moves around. A diamond’s fire is determined by the cut’s crown height and angle and the size and number of facets on the diamond. Therefore, the angles, cut and faceting of the diamond are all essential in determining the beauty of the diamond. When considering cut, be sure to also look at the proportions of the diamond and it’s measurements. This can oftentimes help you decide between two diamonds in the same cut range.

A diamond’s brilliance is rather a complex integration of angles and proporations. It represents the diamond’s light return based on how the light enters, bounces around and returns to the human eye. The brilliance consists of multiple factors based on faceting, and patterns. Poor light return from a diamond (diamonds that exhibit light leakage) will lack optimal beauty. They will look, darker, duller or lifeless. The best way to think about it is a window. A dirty window will make it look dull, dark or murky outside. Also, misshapen windows (concave or bent), will affect the outdoor visibility. Diamonds are similar in that without perfect faceting, the light’s performance and visibility are reduced.

Fire described flashes of color resulting from spectral separation or dispersion of white light into primary colors. Fire is the reason you see blues, oranges, reds, purples, etc. in a diamond. The more colors, the better. This is similar to how light produces a visual rainbow after or during rain.

So how is the brilliance or fire optimized in a diamond? Well, it’s typically a combination of tablet facet, crown angle, girdle, pavilion depth, culet and total depth. A rule of thumb is a culet should always be closed. A table shouldn’t be too large or small. Total depth shouldn’t be too deep or shallow. The girdle shouldn’t be thick or very thin. And there is an inverse relationship between crown angle and pavilion angle. If the crown is steep, the pavilion angle should be shallow and vice versa. We recommend diamonds with steeper crown angles and smaller table facets for the highest degree of brilliance or sparkle.

Diamond Cut History

Within nature and in their rough state, an unpolished diamond looks significantly different than a polished diamond. In it’s rough state, diamonds are not commonly used in jewelry. Initially, diamonds were simply polished in their natural shape to reveal some of the sparkle within. As years went by, cut and polish techniques were improved to enable more light to refract and reflect within the diamond. One common diamond cut that developed in the 14th century was the point cut, in which the diamond simple took the shape of a triangle placed upon an inverted triangle. This closely mimicked its shape in nature. Over time the importance of a culet and table was realized so that the diamond would have a more palatable shape for jewelry. However, these advancements did not create the sparkle, fire, and scintillation that is seen in modern cut diamonds.

In 1476, a master diamond cutter experimented with adding triangular facets to diamonds to unleash their sparkle. Thus the modern diamond was on its way to being shaped and formed. This developed into the rose or antique cut which has large and open facets that may not be symmetrical. The asymmetry is a result of diamonds being cut to preserve weight as well as hand-cutting techniques. Eventually in the 1900s a master diamond cutter named Tolkowsky acertained better diamond proportions taking sparkle and fire into consideration to produce a diamond with extraordinary brilliance. The modern brilliant cut diamond is a result of his efforts and research. Over time, diamond cut became standardized due to the efforts of diamond cutters to adhere to similar practices and diamond cut grades. Today, diamonds are machine cut to ensure maximum precision. Varying grades can be the result of the nature of the rough diamond as well as derire to preserve carat weight and minimize the appearance of inclusions.

The Diamond’s True Size or ‘Spread’

Spread or the diamond’s measurements is the simplest concept for a buyer to grasp. Diamond’s with greater spread (less total depth) mean the diamond looks larger. Most cut grading systems don’t account for spread, which is interesting given the fact that it is the easiest cut-related metric to examine.

While larger looking diamonds are not necessarily more sparkly, they are considered more desirable and often have a premium. Two diamonds can have the same carat weight, but the one with larger measurements has more spread. Spread is not related to the diamond’s carat weight. It is actually the total depth percentage that dictates the spread. That means the width/length against the height. In general, we recommend diamonds in the excellent cut range with the maximum measurements so you can achieve the best of both worlds. You may pay a slight premium for this but it will be well worth it as you will be getting the best of sparkle and size.

Expert Buying Tips

Try and maximize on the cut score and grade of the diamond. This represents the sparkle of the diamond and can help mask (or make up for) lower clarity grades, color tints, or smaller than desired carat weights. You may find value in a “Very Good” cut diamond that have most of the technical aspects of a Excellent cut diamond, but missed the cut off by a technicality such as a thick girdle or larger table facet.

Fill out the short form below and we’ll have our experts match you with a perfect stone!

Diamond Shapes – Most Popular Diamond Cuts

When you think of diamonds, you might picture the classic round diamond shape, which is by far the most popular. But if you’re looking for something different, there are plenty of other shapes available to match your distinct style and taste. Since each diamond shape is cut to different specifications, they reflect light differently, giving each shape its own fire and brilliance.

Popular Diamond Shapes

Choosing the right diamond can be difficult for many people. We hope this information provides you with a basic understanding so you can confidently move through the process going forward. At Wixon, we strive to offer our clients the highest quality diamonds and carry the largest selection of loose diamonds in Minnesota. Our collection of diamond jewelry features many different shape options, ranging from traditional to fancy. Below you will find a comprehensive list of the most popular diamond shapes and their characteristics.

Round Brilliant Cut Diamonds

The round brilliant cut is the most popular shape of diamond. For hundreds of years, diamond cutters have been working with this cut to maximize its brilliance and fire. While this cut offers great flexibility within the four Cs, you will want to select higher quality grades to bring out the most brilliance within a round diamond.

Browse round diamond jewelry

Princess-Cut Diamonds

Princess-cut diamonds are available in both square and rectangular shapes and are exceptionally brilliant because of the way they are cut. The color emitted from princess-cut diamonds is very unique. While the color of other diamonds is displayed mainly in the center, the princess-cut diamonds show distinct color in each of the corners, as well.

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Marquise-Cut Diamonds

Marquise-cut diamonds are the perfect shape for maximizing carat weight by emphasizing the size of the diamond. Its unique shape makes the hands and fingers of its wearer appear longer and more slender. The outline of a diamond is determined by its length to width ratio, which also provides an idea of the shape and look of the diamond.

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Cushion-Cut Diamonds

Sometimes called a pillow-cut diamond, the cushion-cut is a timeless cut that earned its name for its pillow-like shape. Cushion-cut diamonds tend to have impeccable brilliance and clarity in their appearance thanks to their rounded corners and larger facets. These diamonds are available in square and rectangular shapes.

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Emerald-Cut Diamonds

Emerald-cut diamonds have a unique optical appearance because of the rectangular facets step-cut into the diamond’s pavilion. This cut showcases the diamond’s original clarity beautifully because of its large rectangular table which also makes inclusions and color more apparent.

Browse emerald-cut diamond jewelry

Radiant-Cut Diamonds

Radiant-cut diamonds feature uniquely trimmed corners that combine the lines of an emerald-cut with the brilliance of a round diamond. The sparkle of this diamond cut looks beautiful when combined with a variety of other diamond cuts.

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Pear-Shaped Diamonds

Combining round and marquise cuts, the teardrop style of pear shaped diamonds is exceptional. The slender pear shape gives fingers and hands a slimmer appearance while creating a soft and delicate look. Pear shaped diamonds are cut to produce maximum brilliance, so it’s important to look for excellent symmetry.

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Oval Diamonds

Oval diamonds have a classic appearance with a modern twist. It is a popular cut in all types of jewelry, especially in engagement rings, making it easy to match with other jewelry. It has an incredible brilliance, similar to the round brilliant cut, but also has the advantage of accentuating long, slender finders.

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Asscher-Cut Diamonds

Asscher-cut diamonds are often mistaken for an emerald-cut due to their similar cut style. However, an asscher is square as opposed to rectangular. Created in the early 1920s, the Asscher-cut has recently resurged in popularity, especially amongst celebrities.

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Diamond Cuts & Shapes Guide

What is the difference between diamond cut and diamond shape?

Contrary to popular belief, there is a difference between diamond cut and diamond shape. Diamond cut refers to how a diamond is cut and polished so that its facets can absorb and reflect light. A diamond shape is a geometric shape the diamond is cut into and describes its silhouette.

What is a diamond cut?

Diamond cut refers to how well a diamond is cut and polished. The best diamond cut is perfectly proportioned, symmetrical and beautifully polished so that the highest amount of light can enter and reflect out of the stone. A well-cut diamond will appear sparkly and bright, while a poor-cut diamond will appear dull and lack-lustre.

How do you cut diamonds?

How are diamonds cut to shape? Well, diamonds are cut with precision and skill by a qualified diamond expert. The cutting process consists of five parts: planning, cleaving, bruting, polishing and inspecting. After cutting, the diamond is sent for assessment and graded on the 4 Cs (including cut).

Types of diamond cuts

Each diamond is assessed and graded on its cut quality – otherwise known as the diamond cut grade. A diamond cut grade is assessed on several factors such as brilliance, symmetry, polish and fire and ranges from excellent to poor. The higher the cut quality, the more sparkle the diamond is likely to have, so you should consider the cut when buying a diamond.

Excellent cut diamond

An excellent cut diamond is the best diamond cut and also the most beautiful. It means that it is perfectly proportional and has the best brilliance, symmetry, polish and fire. An excellent or ideal cut diamond reflects almost all the light that enters it, so it sparkles beautifully.

Very good cut diamond

A very good cut diamond is almost the same compared to an excellent cut diamond. It still enables most of the light that enters it to reflect but attracts a lower price.

Good cut diamond

A good cut diamond reflects a substantial amount of light that enters it. The diamond does not have the same amount of fire or brilliance that an excellent cut or very good cut diamond has, but it is a more affordable choice for those on a budget.

Fair cut diamond

A fair cut diamond typically reflects a small portion of light. For those looking to maximise the carat weight over other things, a fair cut diamond may be the only choice for a higher carat weight on a budget.

Poor cut diamond

A poor cut diamond is a diamond that has been cut too deep or too shallow. When this occurs, the diamond will lose significant amounts of light. The only benefit of this type of diamond is the price. A diamond that is a poor cut will be significantly lower in price than any other diamond cut grade while also lacking sparkle.

Diamond cut chart

Ever thought about how are diamonds cut to make jewels? Our diamond cut chart illustrates how light passes through different types of cuts. As you can see here, cut quality directly impacts how a diamond sparkles due to the way light enters and reflects from the stone.

What is a diamond shape?

A diamond shape is otherwise known as the geometric shape of a diamond or silhouette. Often, a diamond shape is known as a cut, and the different diamond cuts can be referred to as either round or fancy shape diamonds. Fancy shape diamonds are any shape that isn’t a round brilliant diamond.

Which diamond shapes, cut and sizes are best for brilliance?

Here are our top tips on how to find the most brilliant diamond based on its shape, cut and size.

Choose a better cut quality

A diamond’s cut quality directly impacts how much it sparkles. An excellent-cut diamond is cut with perfect proportions, symmetry and polish to allow as much light to refract as possible. A poor-cut diamond appears dull and lacklustre. That is why if you want a brilliant diamond, you should choose a better cut quality.

Consider diamond size and weight

If you are looking for a large diamond on a budget, you shouldn’t compromise on cut quality because a poor-cut diamond can appear smaller than an excellent cut diamond of the same weight and will not have as much brilliance and fire.

Best diamond shapes for brilliance

Round shaped diamonds naturally have more brilliance and fire. It is possible to choose a cut grade of Good (or better) for a beautiful looking diamond. If a fancy diamond shape is more your thing, it is a good idea to select a cut grade of Very Good (or better) for the perfect symmetry, proportions and polish.

10 Engagement Ring Cuts and Their Unique Meaning

As worn by: Christina Milian, Portia de Rossi, Ashlee Simpson Ross, and Catherine Zeta Jones.

The marquise cut is the ultimate in elegance. Its oval shape meets in pointed ends, resembling the hull of a ship — this cut is also known as the Navette cut (meaning “little boat” in French). In addition to being unique, this cut is also great for someone looking to create the illusion of elongated hands.

Radiant Cut

Illustrated by Durrant Santeng

As worn by: Drew Barrymore, Jennifer Aniston, and Khloe Kardashian.

Similar to an emerald cut, the radiant cut is shaped like an octagon. Unlike an emerald, however, the radiant has 70 light-reflecting facets within it, making it quite the dazzler. “Women who like radiant cuts tend to be bubbly and outgoing,” Landau observes. “The brilliant faceting and rectangular shape is great for those who love a lot of sparkle and flash!

Asscher Cut

Illustrated by Durrant Santeng

As worn by: Pippa Middleton, Gwenyth Paltrow, Zooey Deschanel, and Jessica Alba.

“Asscher cuts have an old world sophistication. Women who love antiques and unique designs tend to gravitate more toward Asscher cuts for their retro look,” she says. Similar to emerald cuts, Asscher cut diamonds have step-cut faceting rather than brilliant-cut faceting, making them understated and elegant. The short, octagonal cut was a hallmark of the ’20s and ’30s and has a distinct Art Deco feel.

Heart Ring Cut

The fiancé: Taylor Kinney
The ring: A 6-carat heart-shaped diamond from jeweler Lorraine Schwartz.
The price: An estimated $500,000
The proposal: February 2015
Called off: July 2016Photo Courtesy of Lady Gaga / @ladygaga

As worn by: Nicki Minaj, Lady Gaga, and Gwen Stefani.

Perhaps the sweetest of all ring cuts, rocking a heart-shaped engagement ring is a bold choice. This is definitely not an engagement ring cut you see everyday, and the women who gravitate toward it tend to stand out in a crowd.

90,000 Evaluation and cutting of diamonds

How is diamond grading and cut

A diamond appraiser is a very interesting, beautiful and difficult profession. There are no two identical diamonds in the world, like two identical people. As diamond manufacturers with more than 28 years of experience, we will try to explain the biggest mystery of how a rough diamond turns into a beautiful sparkling diamond …

There are two main parts in diamond manufacturing:

  • Diamond grading.
  • Diamond cut.

In the process of producing a diamond, a diamond passes from an appraiser to a cutter.

Diamond Evaluation

When purchasing rough diamonds for the production of polished diamonds, we examine the diamonds one by one according to the following criteria: Carat, Color, Clarity and Shape.


Some of the rough diamonds are opaque, which makes their examination difficult and difficult. In this case, we examine the stone through a magnifying glass, looking for a spot on the surface of the stone.This spot is called a “window” and according to what we see through this window, we can determine what will be with the clarity of the diamond after cutting. When trying to determine the clarity of a diamond, we look for inclusions, which are traces of minerals trapped in the stone. Since different shapes can be obtained from raw diamonds, we must determine which shape will be the best for cutting this particular stone. The size and location of inclusions in a rough diamond also influences the decision about its final shape.Often researching and determining the best way to cut a diamond, we are faced with two options: either to make two small diamonds of good clarity from the diamond, or one large, but inferior quality. This decision is extremely important and plays a big role in making possible profits or, conversely, can lead to losses.


We estimate the final color of a diamond when purchasing a rough diamond. The color of a diamond is very important, when evaluating a rough diamond it is difficult to predict the final color after cutting.The color can change, improve or deteriorate, which will dramatically affect the final price of a diamond.

Cutting the diamond

In the first phase, we polish the rough diamond according to the decision made on its shape, while investigating the clarity of the future diamond and looking for options to reduce and eliminate inclusions scattered in the stone.
In the second phase, we define the proportions of the stone. It is important to be very precise in this phase because there can be no mistakes and there is no turning back.

In the third and final phase, we finish cutting the diamond. At this stage, emphasis is placed on symmetry and polishing quality, which are of great importance in the brilliance and play of a diamond.
After the diamond has turned into a beautiful diamond, we boil it at a high temperature in special liquids, removing all the dirt accumulated during the cutting process.

We send the finished diamond to the gemological laboratory, which makes an expert assessment and issues a gemological certificate for this diamond.This certificate resembles the identity card of a diamond, containing all its features and characteristics.
Only at this stage can we see the real price of a diamond and can determine whether our initial estimate of the final result was correct.

Why diamonds lose a lot of weight when cutting: dombusin – LiveJournal

People often wonder why when cutting stones there are such significant losses of weight and size, is it really impossible to cut a precious mineral somehow more economically, doesn’t the cost depend on the size?

For example, the recent pride of Alrosa, sold at an auction, the largest of the Russian pink Ghost of the Rose diamonds after cutting weighed 14 carats, and before cutting – 28 carats.

And the loss of only 50% of the weight of the raw stone is still a very good indicator, especially for the rarest pink diamond. In stones of this color, there is usually a special internal tension that can split a precious diamond with a careless movement of the cutter, therefore, when cutting, the master is forced to bypass all suspicious places. But the “Ghost of the Rose” is unique in its purity, which is why the losses were so small.

Cutting and polishing diamonds is a real science on the verge of art.Although optimal shapes have long been calculated, it is the cutter who makes the final decision about what a diamond should be.

On average, 55-60% of the original weight of the found diamond is wasted during cutting. There are unique crystals of great purity and good shape, in which less than a fifth of the initial weight disappears, but there are also antipodes – diamonds, in which 90% will go to dust.

Large losses during cutting are caused, of course, by the desire of the master to reveal the beauty and potential of a raw diamond, and for this it is advisable to remove all inclusions that will catch the eye.It happens that large diamonds have to be cut into many pieces in order to bypass cracks and contaminated areas – it is more profitable to sell several small diamonds of high purity and polishing class than one, albeit very large, but with visible defects.

Now, before cutting, diamonds are scanned and analyzed using computer programs that help in the best way to circumvent the defects of the raw stone

But the main reason for the large losses of diamonds from cutting lies in the very shape that they are trying to give cut diamonds.

The shape of the finished cut diamond is incredibly important, and it is this that makes the dull, grayish diamond the diamond that pays fabulous money for. The quality of the cut determines the price to a great extent. Poor cut diamonds reflect less light and play less well than perfectly cut stones.

The farther from the ideal shape of the finished diamond, the less light the observer sees in it. It’s all about the direction of the rays of light reflected from the edges, too flat or elongated cut impairs the visible play of light in the stone.

The meaning of the cut is that the light entering the stone is reflected inside it from the maximum number of facets and goes back, then for the observer the stone seems to be glowing from the inside with all its facets.

Perfect cut – when light is reflected from all the edges. This was invented gradually, by improving the form “rose” found empirically in the 16th century, in which the diamonds shone beautifully. And the found “ideal” shape, in which a diamond has exactly 57 facets, was worked out at the beginning of the 20th century and since then 95% of finished diamonds are made according to this scheme.

The loss of only half the weight of the stone when cutting is quite a good result, slightly better than average.

In recent years, with the help of computer calculations, a number of even more complex and beautiful cuts have been derived, for example, 201 facets. But still, the classical form did not give up its positions, because the buyer with a high probability will not understand the difference, but the difference in the cost of the “complicated” cut, in comparison with the classic, will be just significant.

The rest of the cuts, oval, heart, briolette, are more of a compromise, when you really want to keep the maximum weight of the original stone, but the classic shape fails.That is why more expensive colored diamonds are often decorated not in the classical manner – so that more remains. Of course, the cutting of any shape has long been calculated so that the stones also shine very well.

The Pink Star pink diamond was very successfully cut and therefore sold more expensive than originally predicted

So, when a diamond is prepared for a classic cut (which is used by 95% of stones used for jewelry purposes), it is cut into two unequal parts.This is because the usual shape of a diamond is an octahedron, that is, two pyramids connected by bases. And the top of one pyramid is cut off, creating a platform – the future face of the diamond.

There are different options for how to cut a diamond before cutting. And the cutter has to choose in order to strike a balance between beautiful and correct shape and minimization of losses. A large diamond can be cut so that all parts are cut into separate diamonds; for small diamonds, cut corners are lost.

This small cut-off part is the obligatory loss, even if the original stone is very clean and all goes into grinding. Most often, this “loss from cutting” goes to powder for polishing the main part, but if the stone is large and the cut part exceeds at least half a carat, then it can also be cut separately.

Of course, science does not stand still, and new technologies appear to help jewelers. Diamonds, for example, are shined through before being cut, and a special program identifies all internal defects and makes recommendations for the optimal shape.Laser cutting has also reduced waste compared to outdated diamond saws, but nonetheless, the loss of raw material during cutting is still well over half the gemstone, on average.

From Mine to Cutting: Why Diamonds Are So Expensive

Precious Germ

At its core, a diamond is carbon, just like graphite in a pencil. The hardest (not to be confused with the most durable) mineral on the planet. During the formation of our Earth, when magma splashed onto the surface, at high temperature and pressure, graphite turned into crystals, which we know as diamonds.These deposits, in which diamonds are found, are called kimberlite, they are found on all continents (perhaps the exception is Antarctica). The oldest diamond has been proven to be over one billion years old. In general, their age is estimated at hundreds of millions of years.

The process of mining stones is as follows. First, geological exploration is carried out and the locations of possible deposits are determined. Next, soil samples are taken and the content of diamonds in the rock is determined. If the content of gem-quality diamonds in the deposit exceeds 2 cards (0.4 grams) per ton of rock, the mining project is considered economically viable – and the company, which received a license from the government of the country where this deposit was discovered, starts mining. A mining and processing plant is under construction, where ore begins to flow. Depending on the characteristics of a particular deposit, different enrichment methods are used (extraction of diamond from the soil). This is the first stage that affects the cost of the final product. The approximate cost of starting the development of a kimberlite pipe, depending on the complexity, starts at $ 300 million.

Diamonds are also found in rivers and coastal areas near kimberlite deposits. You’ve probably seen films where workers sift soil from the bottom of a river through a large sieve. When the river flows through the kimberlite pipes, it washes away the rock and carries it into the open ocean, in which case diamonds can be found along the entire length of the river. The rock settles on an uneven river bottom, from where it is extracted by special dredges, on which the ore beneficiation process takes place.

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From diamond to diamonds

After the diamond has been obtained, the mining company sells it through an auction or under direct contracts to large polishing factories. The largest rough diamond auctions are held in Antwerp and Johannesburg, from where diamonds are bought by companies located mainly in Israel and India. After a careful study of the crystal by gemologists and cutters, identifying all the weaknesses (if improperly processed, the diamond can explode), a decision is made on what shape the diamond will be.Usually the decision is made based on the maximum value that can be obtained from the sale of the resulting diamond. Maximum characteristics in terms of cut quality fade into the background. A poorly cut five-carat diamond will always cost more than a perfect three-carat diamond. But it was not always so. In the cutting industry of the USSR, it was believed that the quality of the cut was the main thing. Often losing during processing up to 75-80% of the mass of the diamond. As a result, the cost of a cut diamond was often lower than the cost of a diamond before cutting.After cutting, diamonds are carefully sorted by lot, stones of good quality over 0.3 carats are sent for certification to gemological laboratories. Certification is a separate story, here I just want to mention that parameters such as the color and clarity of the stone are determined by an expert by eye. Until now, there is no precise equipment that can determine these parameters of a diamond with 100% probability.

Alexander Ryumin / TASS

Sell in good hands

The next stage is the sale of lots of diamonds directly to jewelry companies, which will fix the stone in jewelry and sell it on the retail market.Brokers who have clients all over the world are responsible for this stage. This is the third stage of cost appreciation. Brokerage companies, like individual brokers, tend to be located in large centers called exchanges. There are several such exchanges in the world, the largest are located in Israel and India. Antwerp also has an exchange, but its size and offer cannot be compared with the previous ones. As a rule, the exchange is a well-guarded perimeter closed to outsiders, where a complete infrastructure has been created for convenient work.Access here is only possible after a thorough check by the security service. Here are the largest deals for the sale of large lots of cut diamonds. It is important to understand that all cutting industries are located outside the perimeter, and are often located hundreds of kilometers from the exchange. As an example in India, 95% of stones are cut in Surat, and the exchange itself is located in Mumbai.

From the exchange, the main flow of diamonds usually goes to major jewelry centers such as Hong Kong, Antwerp, New York and Dubai, where the offices of the largest jewelry chains and a huge number of private jewelers are located.The explanation for this is simple: each of these cities is a kind of gateway to a particular region of the world. It is at this stage that the largest increase in the price of a diamond occurs. If before that the diamond remained in the professional market, where everyone understands the cost perfectly and the price increases due to real expenses plus a small earnings of the company, now the price of the stone depends very much on who they got into, what the seller is ready to do in order to extract maximum profit. If it’s a well-known brand that has a lot of overhead, then the price of a stone can often go up three to four to five times.This is facilitated by competent marketers who, in order to increase the value, breed myths about the exclusivity of their jewelry, come up with non-existent parameters and properties of diamonds, new names for standard cut types, and many other tricks in order to distinguish their product on the market.

Victor J. Blue / Bloomberg via Getty Images

You need to understand: it doesn’t matter who you bought the diamond from – a private jeweler or a world-famous company. The source of origin of diamonds is the same for both.Only the characteristics indicated in the certificate are of importance. Deposits located on different continents are distinguished only by the amount of high-quality diamonds in the rock, and, accordingly, the average cost of a carat on a particular pipe (Russia, by the way, is far from being in the first place in this indicator). And whether the stone was mined in Yakutia, South Africa or Australia, if the parameters are the same, does not matter.

Diamonds are not forever? The stones produced in laboratories are no longer inferior to natural stones

Transparent, colorless, iridescent diamonds are not the most expensive and rare, but perhaps the most desirable stones.If a man is going to propose to his beloved, he needs to get a ring with a diamond, and more. An unspoken rule obliges the groom to spend at least two monthly salaries on the symbol of his love.

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This “old” custom arose only in the middle of the 20th century through the efforts of De Beers marketers, but it has become firmly established in many cultures, including the Russian one – just look at the windows of jewelry stores. However, there are plenty of other diamond jewelry too.Buy them for a variety of reasons or just like that – who doesn’t like shiny things?

But now buyers have an alternative: seemingly exactly the same stones, but much cheaper and not mined in mines at the end of the world, but produced in laboratories and factories.

How artificial diamonds are made

Diamonds are cut diamonds, and those are just carbon, like graphite, coal or graphene. The difference between these substances is in the arrangement of carbon atoms: in diamonds, they form a special crystal lattice.Under normal conditions, such a grid does not work: diamonds are formed at a depth of several kilometers in unbearable heat and under colossal pressure, and they are mined in places where rocks from the depths reach the surface.

Because of their unsurpassed hardness, diamonds are not only valued by jewelers. The demand for them is high, they are expensive, and they are not so easy to dig, especially in Russia: the largest deposits are located in the Arctic Circle. Back in the late 1930s, scientists calculated that diamonds can be synthesized – all that is needed is a temperature of about 2 thousand.degrees and pressure more than 60 thousand atmospheres. In the 1950s, the first artificial stones were obtained in Sweden, the USA and the USSR. The method was named so – high pressure and temperature (English high-pressure high-temperature, or HPHT).

A decade later, the second widespread synthesis technology was developed – chemical vapor deposition (CVD). A substrate or a diamond grain is placed in the chamber, then gases are supplied inside, which are exposed to microwave radiation or a laser.The gases are heated to the point that they turn into plasma. The released carbon atoms fall onto the substrate, almost like snow in winter – a stone forms in a few weeks.

Stand for studying the optical and luminescent properties of diamonds

© Kirill Kukhmar / TASS

In the 1970s, the production of artificial diamonds exceeded the production of natural ones. These diamonds were suitable for technical needs, primarily for the manufacture of cutting tools, drills, etc., but there was no way to make jewelry out of them – they looked like ordinary-looking stones of yellow or brownish color.The first diamonds suitable for cutting were created at about the same time, but the process was too complicated – it was more profitable to continue cutting diamonds from mineral raw materials.

Why are jewelers interested in “synthetics”

Until recently, the jewelery industry lived without noticing artificial diamonds. But both HPHT and CVD technologies have improved. The engineers figured out how to get rid of the brown tint. Moreover, they have learned how to make colored diamonds: blue, pink – such stones are valued at times, and sometimes orders of magnitude higher than usual.One such company, New Diamond Technology, is located in Sestroretsk, Russia. Its president, Tamazi Khikhinashvili, said that New Diamond Technology recently updated its own record: they cut an orange diamond weighing about 20 carats (4 grams) from a crystal almost three times larger – no one has yet succeeded in this.

BARS ultra-high pressure unit used to produce artificial diamonds

© Kirill Kukhmar / TASS

According to the General Director of the Guild of Russian Jewelers Eduard Utkin, even a specialist with a magnifying glass will not guess that the diamond is artificial – this requires equipment for $ 10 thousand.”In terms of physical, chemical, optical properties, they fully correspond to natural ones,” says Utkin.

Since artificial stones, in fact, do not differ from those mined from underground, then they should be considered real diamonds, jewelry – this was the decision of the US Federal Trade Commission in the summer of 2018: producers of “synthetics” were allowed to sell their products without derogatory remarks … In Russia, the opposite is true. “According to the law, analogs of natural materials do not belong to precious stones.If the origin of the stone is not natural, there should be an indication of this on the tag “, – explains Utkin.

In addition to their appearance, artificial diamonds have one more advantage: their production costs have decreased recently. If in 2008 it cost about $ 4,000 to make a 1-carat CVD diamond, then in 2018 it was only $ 300-500. As is the case with jewelry, the retail price of such a stone is about ten times more, but still lower than that of a natural diamond. The most striking thing is that two years ago the difference was only 20%, and now it is 50%.

What will happen to the diamond market

True, prices for different brands are also very different. In 2018, De Beers shocked everyone by creating a low-cost imitation diamond jewelry brand called Lightbox. In the 20th century, the corporation controlled almost the entire diamond market, and it is its merit that a romantic veil has developed around the sparkling stones: “Diamonds are forever” – the slogan of De Beers. The Lightbox felt like a shot in its own foot, but perhaps the company just decided to squeeze out competitors by dumping: gizmos with three-quarters of a carat stones – the size of a notebook cage – cost $ 600 plus the cost of the pendant or studs.Other companies find it difficult to offer a better price than this.

The color of a diamond is determined by comparison with others

© REUTERS / Yves Herman

De Beers has a different explanation: each natural diamond is unique, like a snowflake, and in the laboratory they make whatever they want. Standard diamond – standard price. Eric Lindbergh, head of the Spence Diamonds chain, has a different opinion: he believes that all artificial diamonds are also unique due to the smallest changes in the conditions in which they are grown.In his opinion, it is even important whether the manufacturer uses renewable energy sources and whether it treats employees well.

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The development of the market – and the price of natural diamonds – depends on who can convince buyers. De Beers’ message is simple: both natural and imitation diamonds are good, but they are two different products. Opponents object: no, the laboratory stone is no different, but it costs less, and besides, barefoot children from Angola didn’t dig it at gunpoint, injecting it in two shifts for a bowl of cassava.According to Eduard Utkin, “synthetics” pose a threat to consumer goods, and buyers of luxury items are interested in the origin of diamonds.

But whichever idea wins, according to the consulting firm Bain & Company, natural diamonds are likely to fall in price over the next decade. The only question is how much. The latest report from the Dutch bank ABN AMRO says that artificial stones are already competing successfully with small and second-grade diamonds and, over time, will also become a tempting alternative to large and clean ones.”The future of natural diamonds is uncertain,” ABN AMRO analysts conclude.

“This is the story of new diamonds”

It is profitable for manufacturers of artificial diamonds to sell them to jewelers, but, according to Bain & Company experts, this business will become less profitable over time. More opportunities lie in high-tech sectors of the economy. Crystals are not only very hard – they are also transparent, can serve as excellent semiconductors, and have good thermal conductivity. “Diamonds work in very harsh conditions, therefore they are interesting for the military, for nuclear energy, space research, aircraft navigation systems,” adds Tamazi Khikhinashvili.

Grown diamond crystals

© Valery Sharifulin / TASS

The problem is that, due to the high price and the notorious uniqueness, natural crystals are not suitable for mass use. “When we drew up the business plan, we expected that 90% of our product would be used in electronics, laser technology, computers, radio devices, medical equipment, cutting materials, to determine the hardness of other materials. But at first, our product was not in demand. that you cannot make two identical things out of natural diamonds: there are no identical stones.And we can produce a diamond with the required properties to order, “says Khikhinashvili.

According to him, the producers of artificial diamonds need state support, and now they are fed by the “jeweler”. The money earned is used to conduct research and testing so that the crystals can be used in technology. Khikhinashvili says: “You see, yes? You do two businesses: one supports the second. The second is tomorrow, this is the future.”

Marat Kuzaev

90,000 How are diamonds processed? Description of the tools used to polish diamonds to make diamonds.Cut history Stones and minerals

Diamond is a natural mineral that is carbon with an allotropic crystal lattice. Due to its molecular structure, it is an extremely hard material that can be stored indefinitely.

The chemical composition of a diamond can be changed under the influence of various factors: high temperature, pressure and / or vacuum. As a result of their action, the diamond turns into another chemical element – graphite, which has a different composition of qualitative characteristics.

Diamonds are obtained by natural mining and artificial production. In the second method, the chemical element graphite is exposed to high temperature and pressure.The graphite material changes its molecular structure and turns into rough diamonds, acquiring characteristic strength properties.

The obtained raw material needs additional processing before further use. The factor of increased diamond hardness requires a special approach to the methods of its implementation.


The history of diamond mining is extremely young.This is due to the complexity of the search and extraction of the mineral, as well as the difficulties associated with its processing. The technology of processing the described material with the help of another diamond began to gain popularity only by the XIV-XV centuries AD. Until that time, this method was used only by ancient Indian masters, who carefully kept the secrets of the technology.

On the territory of Russia, the development of mineral deposits and the development of technologies for its processing took on an industrial scale only in the second half of the 19th century.Today in Siberia, work is underway to extract this mineral at mines that are in the list of the largest in the world. At the same time, all types of diamond processing have been mastered.

Processing features

The processing technology and the set of technical devices suitable for this are determined by the name of the final purpose for which the cut diamond will be used.

The characteristics of diamond necessitate its use in various technological systems, tools and devices. For example, a fine diamond fraction – grit, is used as a spraying coating on the working surfaces of any cutting devices. Diamond spraying is used for application on cutting discs, saws, bands designed for sawing metal, stone, concrete, ceramics and other materials.

Despite the resistance of diamond to a wide range of destructive loads, it is a brittle material .The use of impact-pressing technology makes it possible to grind diamonds into chips. The crushing of the mineral is carried out using a hydraulic press (this processing option is rarely applicable).

Roll grinding technology is more widely used. As part of this process, the raw material is fed through a conveyor into a special chamber, in which cylindrical rollers in contact with each other rotate. Passing between them, rough diamonds crumble.Considering the strength factor of the diamond, the conveyor uses several blocks with rotating rollers that have different sizes of the gap between them. This makes it possible to reduce the load on the mechanism, since stage-by-stage crushing is carried out according to the principle from larger to smaller.

The working surface of the rollers is coated with a diamond coating, since no other material can withstand this load in such an effective equivalent.

The size parameters of the crumb fraction are determined by the name of the final purpose for which it will be used. Coarse diamond grit is used for rough processing of materials with an increased strength factor: ceramics, granite, porcelain stoneware. For example, coarse chips are used as a cutting element applied to the working edge of circular crowns intended for cutting round holes in hard materials: ceramic tiles, concrete, granite slabs and others.

Diamond grit of finer grain size is used for fine processing of certain materials. As part of this processing, materials are smoothed, polished, polished. Polishing is done with a special paste based on diamond dust. Diamond grit of different grain size is obtained by crushing and subsequent sieving.

Passing crushed diamond through mesh panels with different mesh sizes allows to obtain fractions of a fixed diameter.

The process of obtaining diamond materials suitable for industrial applications is a more laborious procedure than impact-pressing technology. These materials include, for example, glass cutting wheels, turning tool tips and others. They are elements made entirely of diamond mass. The production of such additions involves carrying out production procedures associated with resource costs and the use of several processing technologies at the same time.

The strength properties of diamond make it much more difficult to manufacture parts that place high demands on dimensional parameters and shape accuracy.

The only material that can be used to effectively process rough diamonds is the diamond itself.

The right combination of factors affecting the machining tool and the material to be cut allows for maximum machining efficiency. For example, in some cases, the workpiece to be processed is heated within a mid-temperature range and the temperature of the processing tool is kept in the low thermal range. In this case, the heated workpiece can be machined, and the percentage of tool wear is reduced.

The use of this method is due to the properties of diamond, which it acquires under the influence of high temperatures.The higher the temperature, the lower the hardness factor of the mineral.

How to make a split?

Another way of working diamond is working with hot iron. This mineral is capable of entering into a chemical reaction with a metal heated to high temperatures. Hot iron begins to absorb the carbon component of the diamond.At the point of contact of a hot metal with a mineral, the latter melts at the molecular level.

This method has low production efficiency, however, only with its help it is possible to achieve certain results in the processing of diamond material.

Application of the hot steel method is carried out when it is necessary to cut a large volume of raw materials with a minimum waste ratio. This method uses glowing steel wire driven by rotating shafts.In this case, the cutting line is as thin as possible, and the loss of the main raw material is minimized.

With the hot sawing method, only general machining operations can be performed. Detailed cutting is carried out using more sophisticated grinding technologies. Hot drilling technology is also used within this method. In this case, the drilling steel element is also heated to high temperatures.The effectiveness of the method also increases due to heating of both parts as a result of friction against each other.

Diamond drilling is used for roughing operations. Holes of the required diameter are drilled along the split line of the workpiece. Special anchor expanders are immersed in them. The technology makes it possible to control the expansion of the anchors one by one or simultaneously.Thanks to this, it becomes possible to perform controlled splitting of the workpiece along a given line.

The angle at which the holes are drilled plays a key role in the effectiveness of the method. Any deviation from the specified values ​​can lead to impaired splitting accuracy.

What is diamond polished?

The main direction in the processing technologies of this mineral is its grinding.Thanks to this procedure, diamonds take their final shape, and in some cases turn into precious stones.

When making diamonds, craftsmen use the methods of stage-by-stage processing. The rough workpiece is cleaned of impurities of other minerals, if any. Then a rough sawing is performed, due to which the main shape of the future product is formed. After that, cutting begins.

For grinding a diamond mineral, devices are used, equipped with special attachments – discs or plates having a thickness, shape and material of manufacture corresponding to the name of the procedure being performed.The working surfaces of these attachments are coated with fractions of diamond chips of various diameters.

If the cutting is carried out with the aim of obtaining a precious stone – a diamond, then a variety of tips with a wide range of dimensional parameters are used. The first to be used are plates or discs with diamond grit of the largest diameter. As the process proceeds, the granularity of the nozzles decreases.The final polishing is carried out using diamond nanoparticles.

Tools used for cutting differ in purpose and principle of operation. Some of them function due to the presence of the rotary motion of the rotor, on the end shaft of which a grinding disc is attached. Other tools work on the principle of reciprocating motion. Grinding plates are inserted into the special clamps of these tools.

During processing, diamonds are ground to a transparent glassy state. Due to the fact that the facets of the future diamond are located in strictly verified positions and at a given angle, the rough raw material is transformed into a precious stone. At the last stage of processing, it is polished to a mirror-like state.

It takes a huge amount of time (sometimes years) to reproduce the entire process, which is explained by the mineral’s resistance to external influences.

Interesting information about diamond mining and processing can be found in the following video.

Diamond quality

Translation from the GIA website

This article is written with the general jewelry consumer in mind.It outlines the most general concepts of quality diamonds, which will help the buyer navigate when choosing their product among the vast assortment offered by retail chains. The GIA (Gemological Institute of America) is the most authoritative organization for the research and evaluation of gemstones. They work there the most qualified specialists in the world. GIA report (conclusion on the quality of the stone) – is considered absolutely reliable and is recognized all over the world.

The very first thing a diamond buyer needs to learn is that they are all different. Each diamond is unique. Diamonds are different sizes, shapes, colors, and they all have different internal characteristics.

All diamonds are very valuable stones. First of all, because it is a rare stone. However, some diamonds are more valuable and rare qualities and characteristics than others.

Specialists-gemologists use a certain system to evaluate diamonds. Otherwise, there would be no way to compare one diamond to another.To do this, they use a diamond grading system developed by the GIA in the 1950s. This system is based on 4 characteristics of a diamond: clarity, color, cut and carat weight.

To enhance the beauty of a diamond, it is shaped to best fit this unique stone.

These are known as 4K (Clarity, Color, Cut, and Carat Weight). Together, they determine the quality of a diamond. The evaluation of the finished diamond is based on this combination.

Often the rarity of one or more of the 4K grades affects the grading of a diamond.Colorless diamonds are less common, most diamonds are tinted yellow or brown. Therefore, a colorless diamond ranks higher on the color scale than a light yellow. Cost and rarity are linked: in this In the case of a colorless diamond, it is rarer and more valuable than a diamond with a slight admixture of yellow. The same ratio between rarity and there is a price to pay for clarity, cut and carat weight.

4K defines the individual qualities of a diamond, and the value of an individual diamond is based on those qualities.Terms used in this system, accepted internationally and used by professionals to describe and evaluate individual diamonds.

Today, descriptions of each of the 4Ks are more accurate than those that apply to any other consumer product. And they have a long history. Three of them: color, clarity and carat weight served as the basis for the very first diamond grading system established by in India over 2000 years ago.


Minor differences in color can significantly affect the value of a diamond.Two stones of the same clarity, weight and cut may differ materially in value based on color estimates only. Even the slightest hint of color will drastically reduce cost. diamond. This emerald cut diamond is colorless and classified in color class D.

In the standard color range, the closer a diamond is to colorless, the higher its price per carat. A particularly large jump is observed in the price of colorless diamonds that are extremely rare. Diamonds come in a variety of colors.Diamonds ranging in color from colorless to light yellow and brown are within the standard color range. In this range, colorless diamonds are the rarest, therefore they are more valuable. They set the grade for grading and prices for other diamonds in a standard range of colors.

These diamonds, graded as E, K and Z, represent the color near the top, middle and bottom of the GIA color scheme.

In the GIA laboratory, the color of diamonds is determined under controlled conditions by comparing them with standards – round diamonds of a known color.

In order to avoid possible errors in assessing the color of a diamond, the evaluators compare it with master stones that represent known GIA colors from D to Z. The

GIA D-Z Scale is the industry standard for color grading of diamonds. Each letter represents a range of colors, based on the tone of the diamond and its saturation.

Many diamonds are fluorescent. (Fluorescence is a phenomenon where a substance absorbs radiant energy of one wavelength (color), and highlights (shines) in a different light range (in a different color) – approx.translator). Diamonds emit visible light after exposure ultraviolet (UV) radiation. UV radiation is invisible to the human eye, but is contained in sunlight. Fluorescent lights him too emit. Under the right conditions, fluorescence can be observed in about 35 percent of precious diamonds.

The most common fluorescent glow in diamonds is blue. But it can be white, yellow, orange or some other color.

Strong blue fluorescent light can cause a light yellow diamond to appear almost colorless in sunlight.Blue and yellow are opposite and tend to cancel each other out so that blue fluorescent light masks yellow. If the fluorescence is too strong, the stone may appear cloudy or “greasy” and this may lower the value of the diamond.


There are few absolutely perfect things in nature. This statement fully applies to diamonds. Diamonds contain various inclusions and irregularities called spots. Together they determine the clarity of the stone.Cleanliness is the relative absence of inclusions and stains.

Among other things, there may be scratches and chips on the surface of a diamond. Inclusions, as a rule, are located inside the diamond and some of them can destroy the surface of the stone. Sometimes, during the growth of a crystal, tiny crystals are trapped inside it. diamond or other mineral crystals. Depending on where they are located, they may remain after the stone has been cut and polishing, which can affect the appearance of the diamond.

The clarity characteristic of a diamond can have a negative impact on its value, but at the same time, it can have a positive effect. For example, it helps gemologists to distinguish diamond from fakes. (This is easier for a diamond with inclusions than for a flawless one.) Since no two diamonds do not have completely identical inclusions, this helps to identify individual stones. They can also provide scientists with valuable information on how diamonds are formed.

There are no two diamonds with exactly the same clarity characteristics and inclusions in the same places.This fact helps geologists identify individual diamonds.

As with other characteristics of a diamond, the effect of clarity on price is directly related to the concept of rarity. Flawless is the highest grade in the GIA classification system. Diamonds graded flawless have no visible inclusions or blemishes when viewed from 10x magnification (10X) by a qualified and experienced evaluator.

As the clarity increases, all other things being equal, the price of a diamond per carat also increases.

Flawless diamonds are so rare that you can work your whole life in the jewelry industry, and never see one, such diamonds dictate the most high prices.

At the other end of the scale are diamonds with inclusions that can be easily seen with the naked eye. Between these two extremes there are diamonds with inclusions that are visible only under 10x magnification. Stones in the middle range make up the bulk retail market.

There are 11 cleanliness classes in the GIA system: flawless, internally flawless, two with very, very small inclusions, three categories with few inclusions and three categories with inclusions.The cleanliness class depends on the quantity and quality of inclusions and stains.

The GIA clarity scale includes eleven diamond clarity grades. The scale narrows at the top, because there are very few diamonds the highest purity.

Sometimes one of the factors plays a big role in assessing the clarity of the stone. The relative importance of each factor varies from diamond to diamond. For example, inclusions located immediately below the top face have a greater influence on the cleanliness rating than those located on the periphery of the stone.In this case, position may be the determining factor.

The characteristics that influence the determination of the clarity of a diamond are determined by 5 factors: size, number, location, the nature, color or relief of the inclusions.

If the nature of the inclusions is such that they can lead to damage to the stone, then this will significantly affect its assessment. However, such cases are rare. and are found only for classes “I”.

Professionals use a set of terms that originally included: very, very slightly imperfect, very slightly imperfect, a little imperfect and imperfect.In recent years, the term imperfect has been replaced with inclusions. (The GIA uses these terms when purity classification.)

These terms were shortened to VVS, VS, SI and I. The abbreviations eventually gained acceptance within the international diamond community. Their use is now widespread regardless of how the words are translated into different languages. Let’s say in France can be translated as “très petites inclusions”, but its abbreviation will remain VS.Even a country like Russia with a completely different alphabet, uses the same abbreviations.


The beautifully cut diamond is dazzling, with every facet showing the skill and professionalism of the cutter. When a diamond interacts with light, every corner and every face affects the amount of light returned to the eyes. This is what brings out all of its splendor.

In the past decade, in the face of increased competition and increased requirements for cutting stones, manufacturers have become more strict approach the quality of their products.Note the proportionality and precision of the faceting pattern in this 1.54 carat diamond.

The proportions of a diamond are determined by how light travels through the stone. If light enters through the crown and exits through the pavilion, the diamond will look dark and unattractive. The proportions of diamonds should be such that, with good polishing, it is better to use light, make a diamond bright, colorful and sparkling.

A well-cut diamond shows all the beauty that a buyer expects from it.

A diamond will look beautiful as a result of a combination of three optical effects: reflection of white light, called brightness, flash lights, called glitter, and a combination of light and dark areas, called glitter. The spatial grid of a diamond is the ratio the size and location of the facets and the contrast of light and dark areas that determine the internal and external reflections of light by the diamond. There must be sufficient contrast between the light and dark areas so that the light passing through the diamond is clearly distributed along the facets.

Diamond manufacturers have known for a long time what proportions best give shine to a stone. However, in recent years, scientists and researchers at the GIA have shown that there are many variations and proportions that will maximize the shine and sparkle of round diamonds.

Generally, the higher the cut quality, the brighter the diamond. Under fluorescent lighting, these diamonds (from left to right) show a strong, moderate and low brightness.

The term “cut” can also describe the shape of a diamond.In addition to the standard round diamond shape, there are others called fancy. Unusual shapes also have their own names. The most famous of them: “marquise”, “princess”, pear-shaped, oval, heart, and emerald cut.

Fancy-shaped diamonds, along with classic round ones, are a popular choice for the modern jewelry consumer.

Carat Weight

Many products are sold by weight: kilograms, ounces, pounds or tons. Even people who have never bought diamonds are used to the idea that weight and price are related.They understand that a large diamond is probably more valuable than a small one. But there are two things that often surprise people when they start learning about diamonds and their carat weight.

The first is the precision with which diamonds are weighed. The weight of a diamond is indicated in metric carats, abbreviated as “carats”. One A metric carat is two tenths (0.2) of a gram – just over seven thousandths (0.007) of an ounce. One ounce contains nearly 142 carats. Small a paperclip weighs about a carat.

The metric carat is subdivided into 100 points. A point is one hundredth of a carat.

Diamonds are weighed to the thousandth (0.001) carat and then rounded to the nearest hundredth, or point. A difference in weight can mean a difference in price in hundreds or even thousands of dollars, depending on the quality of the diamonds.

The weight of a diamond over one carat is usually recorded in hundredths of a carat. For example, 1.03 carats is read as “1 and three hundredths of a carat”. Weight diamonds that weigh less than a carat are usually indicated in points.A diamond that weighs 0.83 carats is voiced as an eighty-three diamond

Large high quality diamonds are rare and valuable stones. This remarkable diamond weighs 100.20 carats and is internally flawless.

The relationship between rarity, weight and price may surprise you. People know that a pound of sugar costs twice as much as a half pound. But diamonds are not the same commodity as sugar. Their price depends on a number of variables, and weight is just one of them. Therefore, it is not always easy to understand or explain why a 1-carat diamond costs, say, $ 6,000, while a 2-carat diamond of similar quality can cost $ 15,000.

In fact, everything is simple: large diamonds are rarer than small ones. The less common a thing is, the more expensive it is. So the big stone will not only cost more, but more expensive per carat. A 1-carat diamond weighs the same as four 0.25-carat diamonds. But even if all other quality factors are equal, then a larger diamond will cost much more than the sum of four smaller ones.

Carat weight can be purely symbolic. Although the visual difference between a 0.98 carat diamond and a 1.01 carat diamond is negligible, many people will choose a larger stone even at a much higher price.Some weights are considered “magic”: half carat, three quarters of a carat, one carat, etc. There is not much difference in weight, but if both colors are D, round and of the same clarity and quality cut, size determines all the difference in price. They really do not differ much by eye, but if the consumer’s heart is focused on the weight of one carat, the difference is huge. The fact that the second stone is slightly larger than the “magic size” of one carat may increase its price by 20 percent due to a difference in weight of only 6 points.

This 1.01 carat oval diamond comes in a 1 carat magic size. When a diamond enters so called “magic size”, the price per carat rises.

Note: Do not confuse carat weight with carat, which indicates the gold content of the alloys.

Types of diamonds

Look at this page of the site.

Expensive and fake Why artificial diamonds will soon replace real ones: Phenomena: Values: Lenta.ru

At the end of May 2018, a very important event took place in the jewelry world: De Beers, one of the world’s leading and most famous diamond mining and processing companies, announced the launch of the Lightbox synthetic diamond brand for a young audience. “Lenta.ru” found out who benefits from it and why “fake” stones can squeeze natural ones.

Diamond, or, in scientific terms, the cubic allotropic form of carbon, is a material in all respects unique. The hardest on the Mohs mineralogical scale of hardness (that is, it can be used to cut all other stones, including the previous one on the scale, corundum – sapphire and ruby).It is also a wide-gap semiconductor and has a very low coefficient of friction on metal (which allows it to be used in metalworking – both in cutting and in drilling), as well as the highest (in comparison with other materials known to scientists) modulus of elasticity and the lowest coefficient of compression.

However, initially a diamond (in faceted form it is called a diamond) was valued for its, so to speak, visual qualities – brilliance and play (in physical language – a high refractive index and dispersion).In ancient times, this stone was very rare, due to the peculiarities of its extraction, and was valued above all other precious stones. Over time, techniques and techniques for cutting diamonds were improved, which made it possible to enhance their brilliance, as well as methods of diamond mining.

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11:44 – March 31, 2018

But the discovery of new deposits in the 19th century (the largest is in the region of the Orange River on the territory of present-day South Africa), and new technologies in mining did not reduce the shortage of natural diamonds, since in addition to their jewelry purpose, they have recently become very popular in science and technology due to their unique physical qualities.By the middle of the 20th century, the need for synthetic crystals with characteristics identical to natural cubic allotropic carbon became obvious.

The development of artificial gemstones began simultaneously in several countries. The Swedes were the first to receive synthetic diamonds in 1953. Since the space race and the arms race were in the center of attention of the leading world powers in the middle of the last century, the USSR was also engaged in synthetic diamonds, which are needed, among other things, in rocketry.In the Union at the Physics Institute of the USSR Academy of Sciences – FIAN – so-called cubic zirconium (cubic zirconium) was created, and then industrial diamonds. They were inferior to the best natural diamonds, but in many respects they suited those for whom they were created, were used for microcircuits, X-ray equipment, telescopes.

Stages of making a synthetic diamond in the Algordanza laboratory

Photo: Christian Hartmann / Reuters

Nowadays even young girls know about cubic zirconia: it is a popular insert in inexpensive silver jewelry of various brands like Pandora and Thomas Sabo.Artificial gem-quality diamonds have not been widely sold until relatively recently – in order for their defining characteristics (purity, on which later the refraction of light and color depends) to correspond to the level required in jewelry, high production technologies and equipment are needed, which, roughly Speaking, it is capable in laboratory conditions to simulate the natural environment in which carbon-graphite turns into diamond, and to accelerate this process, the natural course of which takes millennia, up to several days.

Scientists have developed two main technologies for the synthesis of artificial diamonds, which are not inferior in their physical and chemical characteristics to natural stones. These are HPHT (High Pressure, High Temperature, in translation “high pressure, high temperature”) and CVD (Chemical Vapor Deposition – “chemical vapor deposition”). In the first case, a press is used, an electric current and heating up to 1500 degrees Celsius, in the second, a crystal is formed from a hot reaction gas mixture by condensing it on a special substrate, or, as experts say, on a controlled surface.

It would seem that everything is simple, but in fact, making stones of large size, colorless and high purity is not such a simple matter. CVD technology, which, by the way, is used to apply a scratch-resistant coating on metal surfaces, when trying to grow synthetic crystals does not give the best result: experts note that stones grown, so to speak, from gas do not shine in every sense – in they have a noticeable dark tint, which significantly lowers their jewelry value.HPHT technology has its own problems, as well as the production of very large gem-quality stones, but scientists are also scientists to solve problems.

De Beers’ new Lightbox brand is far from being the first in this business. Many American brands have been making synthetic diamonds for several years now. Some of them are quite remarkable. For example, one of the investors in the large Californian manufacturer Diamond Foundry is Hollywood star Leonardo DiCaprio, and in Helzberg’s Diamond Shops Inc.invested by billionaire Warren Buffett. There are companies that advertise themselves as fighters for ethics in jewelry: for example, American Grown Diamonds tells how harmful diamond mines are to the environment and how immoral it is to oppress low-paid workers at these mines – do not torture nature, buy synthetic.

Diamond rating

Photo: Francois Lenoir / Reuters

The brands LifeGem and Heart In Diamond have brought to life Evelyn Wo’s satirical novel “Unforgettable” and make diamonds from biomaterial: lovers’ hair, baby teeth and, if necessary, from the dust of the dear dead.Debears’ Lightbox has a less macabre marketing strategy: it just counts on millennials, the down-to-earth youth of the new generation who see no point in overpaying for physically identical stones just because natural is found in nature.

And the difference is significant: Lightbox claims that a carat stone for traditional round-cut engagement rings will cost $ 800, which is ten times lower than the price of a natural stone of the same color and clarity characteristics.By and large, this is dumping: as Bloomberg notes, now the average cost of a carat of synthetic stone from other manufacturers is about 4 thousand dollars, that is, not ten times, but only half the price of natural pure stone. Bruce Cleaver, CEO of De Beers, explains the brand’s policy simply: “Laboratory diamonds are nothing special. They are not natural, they are not unique. You can release them all the time, one by one, and they will all be the same. ”

There is a reason for the thrifty millennials position and Cleaver’s outspokenness.It is no secret that most of even natural stones in jewelry lose a third or so in their price immediately after purchase and cannot be considered a serious investment. Of course, we are talking about ordinary small stones that are bought by the majority of consumers all over the world, and not about huge absolutely pure diamonds or colored diamonds of rare shades (blue, yellow, pink) that are unique in their characteristics.

Stock carat diamond

Photo: Brendan McDermid / Reuters

These stones will remain an investment capital and an object of desire for all who can afford luxury jewelry or haute joaillerie.Their price will only grow, because natural stones, unlike laboratory synthesized ones, are a non-renewable resource, and sooner or later natural deposits will be exhausted, although the same De Beers and other diamond miners are systematically reducing the volume of extraction of natural stones: from 145 million carats in 2015 -m to 142 million in 2017. On the other hand, the volume of synthetics production is growing rapidly: in 2014 it was about 360 thousand carats, and in 2017 it was already about 4.2 million carats.

The reasons for this are different: the media often broadcast to the general public wonderful statements about the need to protect nature, ethical production (the sensational film “Blood Diamond” was shot about unethical production with the already mentioned DiCaprio) and respect for nature.In reality, there is a much less sentimental and pretentious reason: a decrease in demand around the world for expensive natural stones due to the economic crisis and the revision of the value system and attitudes towards luxury by young people.

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