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Round Diamond Blog

09/22/2015
by Richard Ribacoff
Round Diamonds in Dallas with Shira Diamonds

ROUND DIAMONDS

Round Diamond in Dallas Texas with Shira Diamonds


The round diamond is the most popular diamond shape, representing approximately 75% of all diamonds sold. Due to the mechanics of its shape, the round diamond is generally superior to fancy diamond shapes at the proper reflection of light, maximizing potential brightness.

Virtually all round diamonds are brilliant-cut, meaning they have 58 facets (57 when there is no culet).

Round diamonds cost more on a per carat basis than fancy shapes for two reasons; the demand for round diamonds is very high, and the yield is relatively low. Because more of the rough stone is lost in the cutting of a round diamond, the cost of each carat retained is higher. A typical round diamond (for example; a 1.00 carat, F-color, VS2-clarity, Ex cut) may cost 25-35% more than a similar fancy shape.

The round diamond began to rise in popularity in 1919 with the publication of Marcel Tolkowsky's thesis "Diamond Design: A Study of the Reflection and Refraction of Light in Diamond". Tolkowsky's work described the ideal proportions of a round cut diamond for maximizing light return (or brilliance) and dispersion (or fire). The original Tolkowsky specifications (53% table, 59.3% depth, 34.50 crown angle, visible culet) have since been modified as the cut mechanics for round diamonds have perfected over time. These theoretical advancements, as well as advancements in technology (such as the use of lasers in diamond cutting), have been adopted by diamond manufacturers to produce the incredibly brilliant cuts we see today in well cut round diamonds.

The table below serves as a general guideline for evaluating the cut of a round diamond. GIA takes these and other factors into consideration when assigning a cut grade.

ROUND DIAMOND - CUT GUIDE

EXCELLENTVERY GOODGOODFAIRPOOR
Table %53 - 58

52 - 53

or

58 - 60

51

or

61 - 64

50

or

65 - 69

< 50

or

> 69

Depth %59 - 62.3

58 - 58.9

or

62.4 - 63.5

57.5 - 57.9

or

63.6 - 64.1

56.5 - 57.4

or

64.2 - 65

< 56.5

or

> 65

Crown Angle34 - 34.9

32.1 - 33.9

or

35 - 35.9

30.1 - 32

or

36 - 37.9

29 - 30

or

38 - 40.5

< 29

or

> 40.5

Pavilion Depth42.8 - 43.2

42 - 42.7

or

43.3 - 43.9

41 - 41.9

or

44 - 45.5

39 - 40.9

or

45.6 - 48

< 39

or

> 48

Girdle

Thin

to

Sl. Thick

Very Thin

to

Sl. Thick

Very Thin

to

Thick

Very Thin

to

Very Thick

Ex. Thin

to

Ex. Thick

CuletNoneVery SmallSmallMedium> Medium
L/W Ratio1.00 - 1.011.02> 1.02


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Polish : Round Diamond

12/05/2015
by Richard Ribacoff
Round Diamonds in Dallas, Texas - Round Diamonds

Polish is graded the same way that symmetry is, Excellent, Very Good, Good, Poor or Fair. When a polish has a grade of Poor or Fair it means that the facets may reduce the intensity of the light that is reflected from a diamond, which means less brilliance or sparkle. They could also have polish lines that are blurring the surface of the diamond giving it a very dirty look. Every diamond cutter, even the most skilled, can run into variances in the grain that no amount of polishing will remove. It is simply a defect that cannot be removed. No amount of cleaning will ever take this look away because the lines are reducing the amount of light that enters the diamond.


Round Diamonds in Dallas Texas : Polish Round Diamonds

It is found that most people want a diamond that has an Excellent or Very Good polish, because even at the Good level the diamond constantly looks like it needs cleaning. Since polishing is graded, it is best to get a GIA (Gemological Institute of America) certificate in order to certify that you have the proper grading to ensure you have the best brilliance you can afford.

Buy the Round Diamond not the Certificate : ONLY EGLUSA and GIA.

11/18/2015
by Richard Ribacoff
How To Buy Round Diamonds not EGL ISrael : Only GIA and EGL USA

Buy the Round Diamond not the Certificate : ONLY EGLUSA and GIA.


About 20 years ago, buying a diamond with a second opinion given on its quality (a certified diamond) was fairly uncommon, but when it was certified you could trust the certification papers it came with. Today, things are very different. The certification of a diamond is often used to mislead the consumer rather than protect them, and here are some of the ways it's done.

Accidental and Fraudulent Grading

A lot of the time a retail jeweler or wholesaler will literally shop for diamonds that are mistakenly or intentionally graded a higher quality than they actually are, so it appears they have great prices. These diamonds are not worth a dime more than their correct grade would dictate, but since the certification says they're better quality than they are , it makes them very easy to sell for some extra profit to unsuspecting consumers.

Another common problem is intentionally, or even fraudulently misgraded certified diamonds. Today there are thousands of companies who make diamond certificates, and in order to take business away from the GIA and EGL they will grade diamonds as being better than they actually are. This ensures that plenty of diamond sellers become and stay their paying customers.

The "Good Guys" Aren't Perfect

The GIA has long been known as one of the most reputable diamond graders but interestingly enough, they have had their share of problems too. About 7 years ago they were charged with thousands, if not millions of fraudulently graded diamonds, as some of the grading supervisors were taking kickbacks from the big companies to grade their diamonds better than they actually were. And, while EGL (USA) and AGS are fairly reliable, EGL (IL) and others are a different story. Diamonds graded by the EGL branch in Israel can easily be four grades lower in quality than the stated grade.

The other well known company is the AGS (American Gem Society). A lot of online diamond vendors and retailers carry AGS certified diamonds and tout them as being one of the strictest grading companies. Well, they might also be saying that because they are paying to be an AGS member and carry their diamonds! When someone pays YOU to carry YOUR diamonds, you may have a slight incentive to grade those diamonds in a way that will benefit your customer (the retailer). I'm not saying they're not a reputable company, just beware of all the hype.

The Certificate Is Still Important

The certificate IS still important – just not as important as the diamond itself. The other problem with most certificates is that the cut (the most important aspect of a diamond) is usually expressed in measurements or an "overall" grade. While you can try to pick a diamond that is close to the ideal proportions, you can't actually see how the diamond sparkles without looking at it. There are over 625 different quality combinations that determine the cost of diamond, and not all of these are listed on the certificate. However, they must ALL interact to create a brilliant looking diamond. I have rejected many "ideal" cut diamonds that look horrible!

It's good to go with a certified diamond and it's better to go with a trusted jeweler or vendor. If you have the option, ask to compare two diamonds with similar grades and judge for yourself how much a difference in color, clarity, or cut there is.

Round Diamonds : Round Diamond Cut : Symmetry and Polish : Shira Diamonds : Largest Round Diamond Dealer in Texas Guaranteed! GIA and EGL USA Diamonds

11/17/2015
by Richard Ribacoff
Round Diamonds in Dallas, Texas - Shira Diamonds - Wholesale Diamonds

The Round Diamond Cut

Need a Diamond Call 972-750-0300.


The diamond cut often refers to two separate characteristics of a loose diamond: (1) its shape, and (2) its make, or style of cutting and quality, which consists of polish and symmetry.

Polish and Symmetry

A diamond's shape as well as its polish and symmetry affect the "behavior" of the stone—simply speaking, how it reflects light. In general, a diamond's cut is all about maximizing the optical light effects that determine the ultimate beauty of the diamond: brilliance (amount of light reflected back to viewer), fire (split of light into a rainbow's colors), and scintillation (glittering of reflected light in the crystal and visibility of dark spots when stone is moved).

Polish and symmetry significantly impact all three of these. In the following picture you can see the most critical parts of a diamond and their names.

Round Diamond Cuts in Dallas, Texas at Shira Diamonds - Learn About Polish and Symmetry in Texas - Shira Diamonds Dallas

To ensure that the diamond has the best brilliance and fire, the best option is to stay away from stones with proportions below the ideal standard. Below you can find the explanation for all facets of a diamond and standards below which you should not buy the stone. The information about such standards can be found in the diamond certificate. GIA calls their certificates diamond dossiers or diamond grading reports while AGS calls theirs diamond quality documents or diamond quality reports.

A diamond's most critical parts:

  1. Diameter of a loose diamond, measured at the Girdle, which is the widest portion of a stone.
  2. Girdle – the middle portion of a diamond stone, its widest part. The Girdle is measured from "extremely thin" to "extremely thick" – the "medium" thickness Girdle is preferred (you can find the information about it in the diamond certificate). Stay away from a "thin" Girdle as it is too fragile and can chip more easily, also do not buy a "thick" one either as it is unnecessarily adding weight to the stone where it matters the least.
  3. Table – the top of the diamond, whose area size ideally should be 53% to 57.5% (in a Round Brilliant) of the Girdle diameter according to the American Gemological Society (AGS) lab studies. Some jewelers say up to 64% is still acceptable. Run away from the diamond with the Table area above 64%.
  4. Depth – in a Round Brilliant, length of the stone from the surface of the Table to the bottom of its Pavilion). Depth should ideally be 58% to 63% of the stone Diameter
  5. Crown – the portion of the diamond between its girdle and its table) – the Crown angle in the well-cut diamond should be 33 to 35 degrees.
  6. Pavilion – in a Round Brilliant, the cone-shaped lower part of the stone:
    a. The Pavilion Depth of the stone, according to the AGS Lab, should ideally be 42.5% to 43.5%. Pavilion Depth is a portion of the overall diamond Depth and represents the height of a diamond Pavilion or the distance from the Girdle to the bottom of Pavilion, called Culet. In diamonds with very deep Pavilions, the entire surface of the Table appears to be dark creating what industry experts call a "Nailhead". On the other hand, stones with shallow Pavilions often produce a "Fisheye" effect due to Girdle's reflection in the diamond's Table. So, if the Certificate specifies the Pavilion Depth is above 43.5% or below 42.5% – the diamond's sparkle will be diminished.
    b. Pavilion angle is another important dimension of the stone, which determines its brilliance and fire. However, many GIA certificates (called Diamond Dossiers and Reports) do not provide information on the diamond's Pavilion angle. So, you will have to rely on the information on the stone's overall quality of the Polish and Symmetry as well its Table size and Depth (all GIA Dossiers and Reports provide this information as a bare minimum).
    c. The relationship between the Crown angle and the Pavilion angle (see above) has the greatest effect on the look of the diamond. A slightly steep Pavilion angle can be complemented by a shallower Crown angle, and vice versa.
  7. Culet – the facet at the bottom tip of a gemstone. The quality of the Culet is typically specified in a diamond certificate – the preferred Culet is not visible with the unaided eye (so, the best one should be graded either "None" or "Medium").

Ratios and proportions of various diamond dimensions in relation to each other are what impact the brilliance and scintillation of the stone most significantly. They determine how well (or not so well) and how much of the light is reflected inside the crystal and back to the surface through the diamond's table. You can find this information on certificate specification enclosed with every certified loose diamond. If the diamond is not certified by one of the gemological labs, then buying such a diamond is not advisable, unless you are a professional gemologist and can certify diamond specifications yourself.

The GIA (the Gemological Institute of America) grades diamonds with descriptive words Excellent, Very Good, Good, Fair, and Poor to convey the quality of the gemstones' Cuts.

The 'polish' grade describes the smoothness of the diamond's facets. The symmetry grade refers to alignment of the facets in relation to each other:

  • Poor polish of the diamond surface can dull the light radiating from the stone. It may also create blurred or dulled sparkle.
  • Poor symmetry can misdirect the light inside the stone as it enters and exits the diamond – the more light is lost due to poor symmetry, the less sparkly the stone would look and the more dark spots you can observe when looking at the diamond from the top.

About Round Diamonds : Facets : Ideal Cut Diamonds : Wholesale Diamonds

11/16/2015
by Richard Ribacoff
Round Diamonds in Dallas - Loose Round Diamond - Diamonds - Diamond - GIA Round Diamonds in Dallas

About Round Diamonds at

Shira Diamonds in Dallas, Texas


Most consumers in today's marketplace choose round brilliant-cut diamonds fashioned to meet modern concepts of beauty. These sparkling gems represent the collective talents of generations of skilled cutters over more than six centuries.


As diamond cuts evolved into today's 57- or 58-facet round brilliants, styles progressed through many stages. By 1750, when the brilliant cut had developed into a style with a circular face-up outline, it had passed through many variations in facet size and proportions. These included table size, crown height, length of the lower half facets, total depth, and culet size.



Round Diamonds in Dallas, Texas - Shira Diamonds

About Round Diamonds part 2 : The Round Diamond Cut : GIA Cut Grading : Wholesale Diamonds in Dallas

11/16/2015
by Richard Ribacoff
Round Diamonds in Dallas - Learn About Diamonds - Wholesale Diamonds - GIA Diamonds

THE GIA CUT-GRADING SYSTEM FOR UNMODIFIED BRILLIANT-CUT DIAMONDS


In 2005, GIA introduced a cut-grading system for unmodified round brilliant cut diamonds. The name "unmodified round brilliant" was applied to a symmetrical round cut with a regular array of 58 facets, cut to modern standards. The system was the culmination of years of research that included the results of preference testing among a wide variety of groups, including trade professionals and consumers.



GIA designed the system to assess the design quality and craftsmanship of diamonds cut in the standard round brilliant style when compared to modern preferences. The system's grades are based on modern-day conventions and assess the proportions that yield the best combination of brightness, fire, scintillation, and pattern. There are five grades: Excellent, Very Good, Good, Fair, and Poor.



Round Diamonds - Cut Grading in Dallas - GIA Round Diamonds : Cut Grading in Texas : Shira Diamonds

European Round Cut Diamonds : Part 3 : Euro Cut : European Cut Diamonds : Learn about Round Diamonds : Shira Diamonds in Dallas : Texas : Round Diamonds Part 3

11/16/2015
by Richard Ribacoff
Round Diamonds in Dallas : European Round Cut Diamonds in Dallas Texas : Shira Diamonds

THE OLD EUROPEAN CUT


Historically, GIA has described unmodified round brilliant-cut diamonds as either "round brilliant" or "old European."


The old European cut was an early evolutionary stage in the progression toward the modern round brilliant. In general, trade professionals characterize old European cuts as having small table facets, heavy crowns, and overall "deep" or "steep" proportions.


European Round Cut Diamonds in Dallas Texas : Shira Diamonds : About Round Diamonds : Wholesale Diamonds

Shria Diamonds : Wholesale Diamonds : Loose Diamonds : Round Diamonds in Anahuac, Texas

11/16/2015
by Richard Ribacoff
Round Diamonds Anahuac - Wholesale Diamonds :: Best GIA Diamonds in Texas

Round Diamonds in Anahuac, Texas at Shira Diamonds

Trust Us, Carat by Carat


Looking for the best round diamond prices in Anahuac, Texas? Shira Diamonds in Texas can help you save on your next diamond purchase. We are a diamond siteholder supplying retail stores, diamond brokers, and diamond wholesalers with loose certified diamonds.


A Sightholder is a company on the De Beers Global SightholderSales's (DBGSS) list of authorized bulk purchasers of rough diamonds. DBGSS is controlled by the De Beers Group, the single largest producer and purveyor of rough diamonds in the world. GBGSS was previously known as DTC (Diamond Trading Company).

Wholesale round brilliant cut diamonds in Anahuac, Texas at Shira-Diamonds.com. This brilliant cut diamond is a 1.51ct I VS2 GIA Certified Diamond. A brilliant is a diamond or other gemstone, cut in a particular form with numerous facets so as to have exceptional brilliance. The shape resembles that of a cone and provides maximized light return through the top of the diamond.

Even with modern techniques, the cutting and polishing of a diamond crystal always result in a dramatic loss of weight; rarely is it less than 50%. The round brilliant cut is preferred when the crystal is an octahedron, as often two stones may be cut from one such crystal. Oddly shaped crystals such as macles are more likely to be cut in a fancy cut—that is, a cut other than the round brilliant—which the particular crystal shape lends itself to.

If you are looking for round loose diamonds in Anahuac, Texas please give us a call at 214-707-1182. We have 1000s of diamonds in stock certified with EGL and GIA.


TO VIEW OUR LARGE SELECTION OF LOOSE DIAMONDS

PLEASE CALL (214) 707-1182

How to save money on a round diamond engagement ring

11/10/2015
by Richard Ribacoff
Round Diamonds in Dallas, Texas : Shira Diamonds : Wholesale Diamonds : Custom Diamond Rings Texas

Looking for the Best ROUND Diamonds

in Dallas, Texas?


Round Diamonds in Dallas, Texas at Shira Diamonds  - Wholesale Diamonds and Custom Diamond Rings


It's not just the festive season that's almost upon us but the peak proposal season, too. Christmas Eve is the most popular day of the year for men to propose, with New Year's Eve not far behind.

Experts say those popping the question don't necessarily need to spend more to get bigger diamonds or more impressive jewellery, they just need to know a few tricks of the trade.

Alastair Smith, a Briton living in Sydney, spent six months researching the market to make sure he got his now-wife's dream ring at the very best price. He's written a book about his search.

How To Buy An Engagement Ring explains what kind of retailers men should approach, how to save thousands of pounds on diamonds, and how to get the exact diamond you want.

"Most men like to think they know their partner pretty well, but the reality is that guys often get it wrong when it comes to engagement rings," says Smith, "The jewellery industry doesn't offer a centralised place for impartial information, meaning that men end up repeating the same mistakes as millions before them. Buying an engagement ring has changed, and there are thousands to be saved if you know what to look for and where to find it."

Before you start diamond shopping you need to understand the "4Cs": cut, colour, clarity and carat. Each diamond is priced individually according to the mix of the 4Cs.

So, now you know what you're looking for, where should you buy it?



The experts agree that anyone buying an engagement ring should give high street jewellers a miss and go online instead.

As with other online retailers, internet-only jewellers can offer cheaper deals as they avoid the overheads associated with running a shop. Make sure you shop around and only buy from a company with a good reputation and excellent, authentic reviews.

As well as saving up to 80% of the cost of a diamond, shopping online at certain sites allows buyers to match up the exact combination of the 4Cs that they want.

"Online has completely changed the diamond industry, as people now have their pick from hundreds of thousands of diamonds and rings, rather than just the handful that their local jeweller stocks," says Smith, "Going online gives guys access to the best choice and the best prices."

Smith eventually bought his fiancé's ring at ShiraDiamonds.com. Other online retailers he recommends include Zales.com, JamesAllen.com, Ritani.com and RobbinsBrothers.com.

If you're on a really tight budget you can give diamonds the swerve altogether and opt for an alternative stone such as a sapphire or zircon. Alternatively check with your relatives to see if there are any heirlooms waiting to be passed down. Not only is this option potentially free but jewellery with history can be much more meaningful and significant.

New Wholesale Round Diamonds : Round GIA Diamonds : Loose Round Diamonds : Wholesale Diamonds : Best Prices in Texas

11/06/2015
by Richard Ribacoff
Wholesale round diamonds in Dallas Texas - Shira Diamonds

The round diamond began to rise in popularity in 1919 with the publication of Marcel Tolkowsky's thesis "Diamond Design: A Study of the Reflection and Refraction of Light in Diamond". Tolkowsky's work described the ideal proportions of a round cut diamond for maximizing light return (or brilliance) and dispersion (or fire). The original Tolkowsky specifications (53% table, 59.3% depth, 34.50 crown angle, visible culet) have since been modified as the cut mechanics for round diamonds have perfected over time. These theoretical advancements, as well as advancements in technology (such as the use of lasers in diamond cutting), have been adopted by diamond manufacturers to produce the incredibly brilliant cuts we see today in well cut round diamonds.

Today we have received over 1.2 Million in loose round diamonds.


Round Diamonds in Dallas, Texas with Shira Diamonds - Wholesale Round Diamonds in Texas.

Round Diamond 1.00ct EGL USA F Si2 $3200.00

Round Diamond 1.00ct EGL USA E SI3 $2900.00

Round Diamond 1.01ct EGL USA D SI2 $4000.00

Round Diamond 1.03ct EGL USA E SI2 $3300.00

Round Diamond 1.03ct EGL USA D SI2 $3500.00

Round Diamond 1.07ct EGL USA F SI2 $2900.00



About Round Diamonds : Wholesale Round Diamonds : Dallas : Texas : Shira Diamonds

11/06/2015
by Richard Ribacoff
Round Diamonds in Dallas - Wholesale Diamonds : Loose Diamonds : Custom Diamond Rings : Shira Diamonds

About Round Diamonds in Dallas, Texas at

Shira Diamonds

13155 Noel Road Suite #830 Dallas, Texas 75240


Round Diamonds in Dallas, Texas - Shira Diamonds - Wholesale Diamonds - Loose Diamonds : Round Diamonds

A brilliant is a diamond or other gemstone, cut in a particular form with numerous facets so as to have exceptional brilliance. The shape resembles that of a cone and provides maximized light return through the top of the diamond.

Even with modern techniques, the cutting and polishing of a diamond crystal always result in a dramatic loss of weight; rarely is it less than 50%. The round brilliant cut is preferred when the crystal is an octahedron, as often two stones may be cut from one such crystal. Oddly shaped crystals such as macles are more likely to be cut in a fancy cut—that is, a cut other than the round brilliant—which the particular crystal shape lends itself to.


Facet proportions and names

Diamond proportions and facets, for the round brilliant cut.

The original round brilliant-cut was developed by Marcel Tolkowsky in 1919. The modern round brilliant consists of 58 facets (or 57 if the culet is excluded), ordinarily today cut in two pyramids placed base to base: 33 on the crown (the top half above the middle or girdle of the stone), truncated comparatively near its base by the table, and 25 on the pavilion (the lower half below the girdle), which has only the apex cut off to form the culet, around which 8 extra facets are sometimes added. In recent decades, most girdles are faceted. Many girdles have 32, 64, 80, or 96 facets; these facets are not counted in the total. While the facet count is standard, the actual proportions (crown height and angle, pavilion depth, etc.) are not universally agreed upon. One may speak of the American cut or the Scandinavian standard (Scan. D.N.), to give but two examples.

Today, Tolkowsky's "ideal" model has been overused. The original model was a general guideline, as there were several aspects of diamond-cutting that were not explored or accounted for in that model.

Because every facet has the potential to change a light ray's plane of travel, every facet must be considered in any complete calculation of light paths. Just as a two-dimensional slice of a diamond provides incomplete information about the three-dimensional nature of light behavior inside a diamond, this two-dimensional slice also provides incomplete information about light behavior outside the diamond. A diamond's panorama is three-dimensional. Although diamonds are highly symmetrical, light can enter a diamond from many directions and many angles. This factor further highlights the need to reevaluate Tolkowsky's results, and to recalculate the effects of a diamond's proportions on its appearance aspects.Another important point to consider is that Tolkowsky did not follow the path of a ray that was reflected more than twice in the diamond. However, we now know that a diamond's appearance is composed of many light paths that reflect considerably more than two times within that diamond. Once again, we can see that Tolkowsky's predictions are helpful in explaining optimal diamond performance, but they are incomplete by today's technological standards.

Figures 1 and 2 show the facets of a round brilliant diamond.

Figure 1 assumes that the "thick part of the girdle" is the same thickness at all 16 "thick parts". It does not consider the effects of indexed upper girdle facets.

Figure 2 is adapted from Figure 37 of Marcel Tolkowsky's Diamond Design, which was originally published in 1919. Since 1919, the lower girdle facets have become longer. As a result, the pavilion main facets have become narrower.

Cut grading

The relationship between the crown angle and the pavilion angle has the greatest effect on the look of the diamond. A slightly steep pavilion angle can be complemented by a shallower crown angle, and vice versa.

Other proportions also affect the look of the diamond:

  • The table ratio is highly significant.
  • The length of the lower girdle facets affects whether can be seen in the stone, under certain viewers.
    • Most round brilliant diamonds have roughly the same girdle thickness at all 16 "thick parts".
    • So-called "cheated" girdles have thicker girdles where the main facets touch the girdle than where adjacent upper girdle facets touch the girdle. These stones weigh more (for a given diameter, average girdle thickness, crown angle, pavilion angle, and table ratio), and have worse optical performance (their upper girdle facets appear dark in some lighting conditions).
    • So-called "painted" girdles have thinner girdles where the main facets touch the girdle than where adjacent upper girdle facets touch the girdle. These stones (such as EightStar-brand diamonds) have less light leakage at the edge of the stone (for a given crown angle, pavilion angle, and table ratio). Some diamonds with painted girdles receive lower grades in the GIA's cut grading system, for reasons explained in the GIA article

Several groups have developed diamond cut grading standards. They all disagree somewhat on which proportions make the best cut. There are certain proportions that are considered best by two or more groups however.

  • The AGA standards may be the strictest. David Atlas (who developed the AGA standards) has suggested that they are overly strict.
  • The HCA changed several times between 2001 and 2004. As of 2004, an HCA score below two represented an excellent cut. The HCA distinguishes between brilliant, Tolkowsky, and fiery cuts.
  • The AGS standards changed in 2005 to better match Tolkowsky's model and Octonus' ray tracing results. The 2005 AGS standards penalize stones with "cheated" girdles. They grade from 0 to 10.
  • The GIA began grading cut on every grading report beginning January 1, 2006 based on their comprehensive study of 20,000 proportions with 70,000 observations of 2,000 diamonds. The single descriptive words are as follows: Excellent, Very Good, Good, Fair, and Poor.

The distance from the viewer's eye to the diamond is important. The 2005 AGS cut standards are based on a distance of 25 centimeters (about 10 inches). The 2004 HCA cut standards are based on a distance of 40 centimeters (about 16 inches).

Polish and symmetry are two important aspects of the cut. The polish grade describes the smoothness of the diamond's facets, and the symmetry grade refers to alignment of the facets. With poor polish, the surface of a facet can be dulled, and may create blurred or dulled sparkle. It may constantly look like it needs to be cleaned. With poor symmetry, light can be misdirected as it enters and exits the diamond.