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Cut is the result of a craftsman's skill in transforming arough diamond into a breathtaking gem. A diamond has facets that allow light to enter it, become refracted, and exit in a rainbow of colors. So it follows that a better cut diamond does a better job of dazzling us with its beauty. Here's the 'secret' to how a diamond sparkles:


diamond cuts, diamond clarity chart


As you can see, the diamond with the correct proportions does a more effective job of refracting light out the top of the stone to your eye. The less-than-ideal cut diamonds allow some light to become lost out the bottom.

  • Diamond Proportions

There are many measurements that go into creating a diamond that truly maximize the refraction of light. Facets must be cut at exactly the right angles relative to one another; the top and bottom halves of the stone must have the proper depth relative to each other; the table, or flat surface on the top, must be the correct size, relative to the overall size of the stone. And, of course, the facets on the top (crown) and bottom (pavilion) must align correctly with each other. Here is a diagram showing a diamond's basic proportions:


diamond carat wt, design engagement ring

These measurements and percentages are different for each diamond, and are all taken into account in the evaluation of a diamond's cut. In fact, each diamond shape (heart, round, oval, emerald, etc.) has its own set of guidelines for what makes a Premium or Good cut.

An 'ideal cut' is a specific set of guidelines that delineate the proportions that give a diamond the highest amount of fire and brilliance.

Although the proportions of an ideal cut vary depending on the source you talk to (from jeweler to jeweler, country to country), there are certain ranges that are generally accepted as capable of evoking the most desirable fire and brilliance from a stone. These ranges must cause the light entering the diamond to be reflected and dispersed through the table (top), not through the sides or bottom.

But most of all, an ideal cut diamond must be cut to bring out the stone's brilliance and fire, not retain the most weight from the rough cut stone.

  • Guidelines

Diamond Select maintains extremely stringent guidelines for diamond quality. All diamonds we offer must fall within specific ranges to be judged acceptable by our staff gemologists.

Below is a table listing each of our three cut grades for a round brilliant diamond (Ideal, Premium and Good). The table percentage given is the measurement of the diamond's table width, relative to the width of the entire stone (at its girdle, or widest point). This relationship is critical for maximum fire and brilliance: too small or too large a table can hamper the diamond's ability to disperse light properly, not to mention possibly causing the stone to appear smaller for its weight.

The depth percentage listed is the length of the stone from table (top) to culet (bottom), expressed as a percentage of the diamond's width, measured at its widest point. This depth-to-width relationship is largely responsible for the diamond's being properly proportioned, resulting in the proper refraction of light and maximum fire and brilliance.

  • Round Brilliant Diamond Cut Grades
Ideal 53% - 57% 59% - 62%
Premium 58% - 63% 58% or 63%
Good 64% - 65% 57.5 or 64%

It's important to note that some independent grading laboratories do not grade a diamond's cut, while others do. The Gemological Institute of America (GIA), for example, will only give an evaluation of the quality of a diamond's cut for round brilliant diamonds. For all other diamonds, only the shape and measurements of the stone are part of the report. It does, however, give the proportions of the diamond (depth and table percentages), girdle thickness, and culet size (if any) as well as a general rating of the stone's finish, including its polish and symmetry.

  • Symmetry

Symmetry describes several factors: how the facet edges align with each other; whether the corresponding facets from opposite sides of the diamond align with each other or not; and whether the facets from the crown, or top of the diamond are properly aligned with the corresponding ones on the bottom (pavilion). When choosing a diamond, look for Excellent, Very Good or Good ratings on the grading report, if symmetry is graded.

  • Fluorescence

When exposed to ultraviolet light, small percentages of diamonds fluoresce, or emit light, which may be yellow or blue. Fluorescence does not necessarily affect a diamond's value, however it is listed on a diamond grading report.

  • The Bottom Line

When it comes to judging cut, the most important thing to remember is that quality and craftsmanship are more important than size, since these characteristics can mean the difference between a positively radiant, lively diamond, and a lifeless, lackluster stone (that may, in fact, be larger). Remember, diamonds have more value if they have been cut to maximize their brilliance, not their size. All in all, cut must be balanced along with the rest of the 4Cs in order to find the highest quality diamond your budget will allow.


The most important thing to know about diamond color is, in general, the less color a diamond has, the more valuable it is, all other factors being equal.

Diamonds are found in nature in a wide range of colors, from completely colorless (the most desirable trait) to slightly yellow, to brown. So-called 'fancy color diamonds' come in more intense colors, like yellow and blue, but these are not graded on the same scale.

The diamond color grading system uses the letters of the alphabet from D through Z, with 'D' being the most colorless and therefore the rarest and most valuable, and 'Z' having the most color within the normal range, and being the least valuable, all other factors being equal. A diamond's color is determined by looking at it under controlled lighting and comparing them to the Gemological Institute of America's color scale, which is based on a set of diamonds of known color. Here is a diagram showing how a diamond's color is graded

  • Diamond Color Scheme
diamond clarity chart, diamonds 4 c's, jewelry gift

Diamonds found in nature come in colors ranging from colorless to slightly yellow or brown, to more rare and costly pink, green or blue stones (commonly referred to as 'fancy' diamonds). Excluding 'fancy' diamonds, the ideal color for a diamond is colorless, although this is extremely rare.

A diamond's color is most accurately determined when it is not mounted in a setting, since settings can introduce tints of their own color into the diamond. This is more evident in yellow gold settings, and less so in white gold and platinum settings. Even a trained professional can't always tell the difference between close grades of color in a diamond if it is still mounted in a setting. For this reason, gemological laboratories such as the Gemological Institute of America (GIA) and American Gemological Society (AGS) will only grade diamonds that are unmounted.

Diamonds with a color grade of D, E or F are considered colorless; G, H, I and J are near colorless; K, L and M have a faint yellow tint; N, O, P, Q and R have a very light yellow tint and S, T, U, V, W, X, Y and Z are light yellow. A diamond that is a D color is absolutely colorless, and is therefore the most valuable. However, it's important to understand that color alone does not determine the value of a diamond. All '4Cs' must be taken into account. A diamond of D color that has imperfections or is poorly cut is not as valuable as a stone of a lower color grade that has a superior cut and clarity.

  • The bottom line

A diamond's color also has a great impact on its cost. Since ''colorlessness'' is the most sought-after trait in terms of color, diamonds that are higher up on the color scale (e.g. D, E, F) will have a greater value. If a diamond with a specific cut, clarity and carat weight is moved to the next color grade, it's possible to see a significant increase or decrease in the per-carat price--all other factors being equal. The idea is to choose a diamond that is as high on the color scale as your budget will allow, taking all 4Cs into account.


A diamond's weight is measured in what is known as a 'carat', which is a small unit of measurement equal to 200 milligrams.

Carat is not a measure of a diamond's size, since cutting a diamond to different proportions can affect its weight. (The word 'Karat' is used to express the purity of gold, and is not used in relation to diamonds.) Here is a diagram that shows the relative size of various carat weights in a diamond that is cut to the same proportions:

Note: the diamonds illustrated are not shown actual size.

  • Carat Weight Scale
2 carat diamond, Engagement ring settings, diamond sizes

The most important thing to remember when it comes to a diamond's carat weight is that it is not the only factor that determines a diamond's value. In other words, bigger does not necessarily mean better. All four Cs-Cut, Color, Clarity and Carat Weight must be balanced in order to arrive at a diamond that fits your budget. None of the 4Cs is mutually exclusive, nor is any one more important than the others.

The word carat actually comes from the word carob (as in carob seeds), which is how ancient cultures measured the weight of diamonds on their scales. In 1913, however, the weight was standardized internationally and adapted to the metric system.

Although they can be measured when mounted in jewelry, diamonds are most accurately weighed when they are not mounted in a setting. In fact, gemological laboratories such as the Gemological Institute of America (GIA) and American Gemological Society (AGS) will only grade diamonds that are unmounted. A diamond grading report will tell you the exact carat weight, to the nearest hundredth of a carat, for that particular diamond. Each Carat is divided into 100 parts called 'points.' So a 1-carat diamond has 100 points, a 3/4 carat has 75 points, etc. Points in a fraction of one carat are measured within ranges, so that a 3/4 carat diamond may have between .69 and .82 points and still be considered a 3/4 carat. Here's a table of size and weight ranges:

  • Carat Fractions and Their Decimal Equivalents:
1/10 = .09 - .11
1/8 = .12 - .13
1/6 = .14 - .17
1/5 = .18 - .22
1/4 = .23 - .28
1/3 = .29 - .36
3/8 = .37 - .44
1/2 = .45 - .58
5/8 = .59 - .68
3/4 = .69 - .82
7/8 = .83 - .94
1.0 = .95 - 1.05

Remember, all diamonds are not created equal. Two diamonds of equal Carat Weight may vary substantially in price due to their Cut, Color and Clarity. Also, a diamond's weight can be 'hidden' in different parts of the stone. For example, you can have a well-cut diamond, whose weight is distributed properly, a diamond that is cut too shallow to make it wider and heavier, but not the most brilliant, or one that is cut too deeply, to add weight to the bottom of the stone - again compromising its ability to radiate maximum brilliance.

  • The bottom line

The carat weight of a diamond is an extremely important determining factor in its value. Diamonds are valued on a per-carat basis. For example, a diamond of exceptionally high quality may sell for $20,000 per carat, while one of lesser quality may sell for $1,000 per carat. So, a three-carat stone could be $60,000 or $3,000, depending on its per-carat price. Diamond values also increase disproportionately as the size of the stone increases. In other words, a two-carat stone will not necessarily cost twice per carat than a one-carat stone. It could cost much more, since diamonds are rarer in larger sizes. As you take a stone of a particular cut, clarity and color and move its carat weight to the next price category, you may see quite a large increase in the price per carat. Remember that size isn't everything. When choosing a diamond, all 4Cs must be taken into account. The key is to strike a balance among them, while still working within your budget.


The clarity of a diamond refers to how clear, or "clean" the diamond is. Diamonds have imperfections which are present in its rough state. The clarity scale is a measure of the severity of those imperfections or "inclusions" as it is known in the trade.

In addition to internal inclusions, surface irregularities are referred to as blemishes. These two categories of imperfections-inclusions (internal) and blemishes (external)-make up clarity. The fewer the imperfections, the rarer and more valuable the diamond.

Clarity is graded using a very precise and complex method of evaluating the size, location, and visibility of inclusions.


diamond clarity chart, Engagement ring settings, diamond sizes
Clarity FL IF VVS1 VVS2 VS1 VS2 SI1 SI2 I1 I2 I3
Scale Flawless-
Internally Flawless
Very Very Slightly Imperfect Very Slightly Imperfect Slightly Imperfect Imperfect

Clarity is a measure of internal structural imperfections called "inclusions". Grades of clarity, which are mostly those used by Gemological Institute of America (GIA), are:


Shows no inclusions or blemishes of any sort under 10 x magnifications when observed by an experienced grader.

IF-Internally Flawless:
Have no inclusions when examined by an experienced grader, but will have some minor blemishes.

VVS1, VVS2 - Very Very Slightly Imperfect:
Contains minute inclusions that are difficult even for experienced graders to see under 10x magnification.

VS1, VS2 - Very Slightly Imperfect:
Contains minute inclusions such as crystals, clouds or feathers when observed with effort under 10x magnification.

SI1, SI2 - Slightly Imperfect:
Contains inclusions such as cavities, knots clouds, feathers and included crystals which are noticeable to an experienced grader.

I1, I2, I3 - Imperfect:
Contains inclusions such as large feathers or large included crystals, which are obvious under a 10x magnification and may affect transparency and brilliance.