Diamond Cut is perhaps the most important of the four Cs, so it is important to understand how this quality affects the properties and values of a diamond.
A good cut gives a diamond its brilliance, which is that brightness that seems to come from the very heart of a diamond. The angles and finish of any diamond are what determine its ability to handle light, which leads to brilliance.
As you can see in the image below, when a diamond is well-cut, light enters through the table and travels to the pavilion where it reflects from one side to the other before reflecting back out of the diamond through the table and to the observer's eye. This light is the brilliance we mentioned, and it's this flashing, fiery effect that makes the displayed examples.
In a poorly cut diamond, the light that enters through the table reaches the facets and then 'leaks' out from the sides or bottom of the diamond rather than reflecting back to the eye. Less light reflected back to the eye means less brilliance.
Don't confuse diamond cut with shape. Shape refers to the general outward appearance of the diamond, not it's reflective qualities.
Good Proportions are key
Most gemologists agree that the best cut diamonds are those that follow a set of formulae calculated to maximize brilliance. These formulae can be seen in a diamond's proportions, most importantly how the depth compares to the diameter, and how the diameter of the table compares to the diameter of the diamond.
One of the leading diamond grading bodies, the AGS, has developed a table which they believe offers the the "ideal" proportions of diamond. The image below details the various parts of the diamond, together with the recommended proportions of the AGS.
Because cut is so important, several grading methods have been developed to help consumers determine the cut of a particular diamond. In general, these grades are Ideal, Excellent, Very Good, Good and Fair.
Meter: The width of the diamond as measured through the girdle.
Table: This is the large, flat top facet of a diamond.
Crown: The upper portion of a cut gemstone, above the girdle.
Girdle: The narrow rim of a diamond that separates the crown from the pavilion. It is the largest diameter to any part of the stone
Pavilion: The lower portion of the diamond, below the girdle. It is sometimes referred to as the base.
Culet: The tiny facet on the pointed bottom of the pavilion, which is the portion of a cut gem below the girdle.
Depth: The height of a gemstone, from the culet to the table.
Which Grade Should I buy? Selecting the grade of cut is really a matter of preference. To make the best selection, you need to understand the various grades. Universal Jewelers grades its diamonds as Ideal, Very Good, Good, Fair or Poor.
Ideal: Diamonds that are described by Universal Jewelers as Ideal have a make which is considered fine by anyone in the industry. This cut is intended to maximize brilliance, and the typically smaller table sizes of these diamonds have the added benefit of creating a great deal of dispersion or 'fire' as well. Ideal quality diamonds are truly for the person who enjoys knowing that he has one of the finest things that money can buy. This category applies only to round diamonds Premium: Diamonds that are described by Universal Jewelers as Premium have a make which is considered fine by anyone in the industry. In the case of round diamonds, many of these diamonds have cuts that are the equal of any Ideal Cut diamond, though they often can be purchased at slightly lower prices than AGS Ideal Cuts. They are intended to provide maximum brilliance and fire. They are truly for the person who enjoys knowing that he has one of the finest things that money can buy.
Premium: Diamonds that are described by Universal Jewelers as Premium have a make which is considered fine by anyone in the industry. In the case of round diamonds, many of these diamonds have cuts that are the equal of any Ideal Cut diamond, though they often can be purchased at slightly lower prices than AGS Ideal Cuts. They are intended to provide maximum brilliance and fire. They are truly for the person who enjoys knowing that he has one of the finest things that money can buy.
Very Good: Diamonds that are described by Universal Jewelers as Very Good are of a excellent make. They reflect most of the light that enters them, creating a good deal of brilliance. With these diamonds, the cutters have chosen to stray slightly from the preferred diamond proportions in order to create a larger diamond. The result is that these diamonds fall slightly outside of some customers' preferences in terms of, for example, table size or girdle width, though, in many cases many of the parameters of diamonds in this range will overlap with certain parameters of diamonds in the Ideal or Premium ranges. Generally, the price of these diamonds in slightly below that of Premium cuts.
Good: Diamonds that are described by Universal Jewelers as Good reflect much of the light that enters them. Their proportions fall outside of the preferred range because the cutter has chosen to create the largest possible diamond from the original rough crystal, rather than cutting extra weight off to create a smaller Premium quality diamond. Diamonds in this range offer an excellent cost-savings to customers who want to stay in a budget without sacrificing quality or beauty.
Poor: A diamond described by Universal Jewelers as poor will reflect only a small proportion of the light that enters it. Typically these diamonds have been cut to maximize the carat weight over most other considerations. We do not recommend this type of cut and to ensure that our customers enjoy only fine, classic jewelry, Universal Jewelers does not offer diamonds that have been graded fair to poor.
When we speak of a diamond's clarity, we are referring to the presence of identifying characteristics on and within the stone. While most of these characteristics are inherent qualities of the rough diamond and have been present since the earliest stages of the crystal's growth below ground, a few are actually a result of the harsh stress that a diamond undergoes during the cutting process itself.
If you think about the incredible amount of pressure it takes to create a diamond, it's no surprise that many diamonds have inclusions-scratches, blemishes, air bubbles or non-diamond mineral material-on their surface or inside. Diamonds with no or few inclusions and blemishes are more highly valued than those with less clarity, not just because they are more pleasing to the eye, but also because they are rarer.
How are Diamonds Created for Clarity
Diamonds are graded for clarity under 10x loupe magnification. Grades range from Internally Flawless, diamonds which are completely free of blemishes and inclusions even under 10x magnification, to Imperfect 3, diamonds which possess large, heavy blemishes and inclusions that are visible to the naked eye. F-IF-Flawless or Internally Flawless. This diamond has no internal inclusions. Very rare.
VVS1-VVS2 - Very Very Slightly included. Very difficult to detect under 10x magnification.
VS1-VS2 - Very Slightly included (two grades). Minute inclusions invisible to the naked eye and seen only with difficulty under 10x magnification.
SI1-SI2 - Slightly Included (two grades). Minute inclusions Can be seen under 10x magnification and in some cases, in SI2, inclusions are visible to the naked eye.
I1-I2-I3 - Included (three grades). Inclusions visible under 10x magnification as well as to the human eye.
While the presence of these clarity characteristics do lower the clarity grade, and therefore the value, of a diamond they can also be viewed as proof of a diamond's identity. GIA certificates include what is known as a "plot" of a diamond's inclusions. Since no two diamonds are exactly the same, comparing the uniqueness of your diamond's clarity characteristics with the plot provided on the diamond certificate offers assurance that the diamond you pay for is the same diamond you receive.
Which Clarity Should I Choose?
While Flawless diamonds are the rarest, and arguably the most beautiful diamonds, a diamond does not have to be completely clean to be extremely attractive. Those diamonds with VVS and VS grades can be excellent choices as well. More affordable are those diamonds which gemologists call "eye-clean" - diamonds with no inclusions visible to the naked eye. These diamonds as SI or SI2.
The table below demonstrates the effect that clarity has on diamond pricing, assuming carat, cut and color remain the same.
When jewelers speak of a diamond's color they are usually referring to the presence or absence of color in white diamonds. Color is a result of the composition of the diamond, and it never changes over time. Because a colorless diamond, like a clear window, allows more light to pass through it than a colored diamond, colorless diamonds emit more sparkle and fire.
The formation process of a diamond ensures that only a few, rare diamonds are truly colorless. Thus the whiter a diamond's color, the greater its value. (Note that fancy color diamonds do not follow this rule. These diamonds, which are very rare and very expensive, can be any color from blue to green to bright yellow. They are actually more valuable for their color.)
To grade 'whiteness' or colorlessness, most jewelers refer to GIA's professional color scale that begins with the highest rating of D for colorless, and travels down the alphabet to grade stones with traces of very faint or light yellowish or brownish color. The color scale continues all the way to Z.
What Color Grade Should I Choose?
Diamonds graded D through F are naturally the most valuable and desirable because of their rarity. Such diamonds are a treat for the eyes of anyone. But you can still obtain very attractive diamonds that are graded slightly less than colorless. And diamonds graded G through I show virtually no color that is visible to the untrained eye.
And while a very, very faint hint of yellow will be apparent in diamonds graded J through M, this color can often be minimized by carefully selecting the right jewelry in which to mount your diamond. Keep in mind that, while most people strive to buy the most colorless diamond they can afford, there are many people who actually prefer the warmer glow of lower-color diamonds.
To ensure that our customers enjoy only fine, classic jewelry, Universal Jewelers does not offer diamonds that have been graded below M.
A carat is a unit of measurement, it's the unit used to weigh a diamond. One carat is equal to 200 milligrams, or 0.2 grams. The word carat is taken from the carob seeds that people once used in ancient times to balance scales. So uniform in shape and weight are these little seeds that even today's sophisticated instruments cannot detect more than three one-thousandths of a difference between them.
Don't confuse it with 'karat', the method of determining the purity of gold.
The process that forms a diamond happens only in very rare circumstances, and typically the natural materials required are found only in small amounts. That means that larger diamonds are uncovered less often than smaller ones. Thus, large diamonds are rare and have a greater value per carat. For that reason, the price of a diamond rises exponentially to its size.