4C's of Diamonds: Cut, Color, Clarity, Carat

Refers to the angles and proportions of a diamond. Based on scientific formulas, a well-cut diamond will internally reflect light from one mirror-like facet to another and disperse and reflect it through the top of the stone. This results in a display of brilliance and fire, thereby placing well-cut diamonds higher on the Diamond Quality Pyramid than deep or shallow-cut diamonds.

Refers to the degree to which a diamond is colorless. Diamond color has a significant impact on its value. The color scale ranges from D to Z, from colorless to light yellow. Warmer colored diamonds (K–Z) are particularly desirable when set in yellow gold. Icy winter whites (D–G) look stunning set in white gold or platinum.

Diamonds with few flaws, or inclusions, are very rare and highly valued. Inclusions are natural identifying characteristics such as minerals or fractures, appearing while formed in the earth. They may look like tiny crystals, clouds or feathers.

Refers to the weight of a diamond. Carat is often confused with size even though it is actually a measure of weight. One carat is equivalent to 200 milligrams. One carat can also be divided into 100 “points.” A .75 carat diamond is the same as a 75-points or 3/4 carat diamond.

4C's : Cut

What makes diamonds stand out beyond any other precious gemstone is their fire and brilliance. While nature determines the color and clarity of a stone, diamond cut is dependent solely upon the skill of the cutter.

The cut of a diamond is what determines how the light that enters the diamond is reflected and therefore how much fire and brilliance the diamond will exude. A diamond that is cut too shallow with respect to its width will allow too much light to pass straight through the diamond, leaving little light to reflect. Such a diamond will appear dull and lacking in brilliance. Conversely, a diamond cut too deeply will allow light to escape from the sides of the diamond, also appearing dull.

The depth and table measurements, which are used to determine how good the cut is, are given in percentages of the girdle (the widest part of the diamond). So, if a diamond's girdle measures 10 millimeters, the table measures 5.6 mm, and the total depth measurement is 6.25 mm, it would have a table of 56% and a depth of 62.5%. What percentages will yield an ideal cut vary from shape to shape. The table below gives percentage ranges of a good cut for different shaped diamonds.

Shallow Cut: Light is lost out the sides, causing the diamond to lose fire and brilliance.

Deep Cut: Light goes straight through the diamond, causing the diamond to appear dark and dull.

Ideal cut: This is a very rare cut that reflects nearly all light that enters the diamond and creates the maximum fire and brilliance.

Premium cut: Reflects almost as much light as the Ideal Cut, but for a lower price.

Good cut: Reflects most light that enters the diamond, but not as much as a Premium Cut diamond. This is less expensive than the Premium Cut.

Fair cut: These still are a quality diamond, but Fair Cut diamonds will not be as brilliant as a good cut.

Poor cut: All the diamonds that do not meet the Fair Cut quality standards are placed in. These diamonds are deep and narrow or shallow and wide and tend to lose most of the light out the sides and bottom. TOG does not carry Poor Cut diamonds.

Depth & table measurements

	Round	Oval	Emerald	Pear & Marquise	Heart	Radiant & Princess
Table:	53 - 60%	53 - 62%	60 - 78%	53 - 60%	53 - 66%	65 - 80%
Depth:	57 - 63%	60 - 72%	60 - 73%	48 - 65%	48 - 65%	65 - 76%

In order to cut a stone to ideal proportions, much of the rough diamond is sacrificed, leaving a stone with a smaller carat weight. Diamond cutters sometimes sacrifice ideal proportions to end up with a larger, more profitable stone. Industry standard valuation of diamonds does not take into account a diamond's proportions, thus a larger diamond with fair proportions will be worth more than the smaller diamond with good proportions to a diamond cutter (color and clarity being equal). Consequently, ideal cut stones are very rare and hard for wholesalers and retailers to find.

AGS 0-Cut

At Diamond Source of Virginia, we like to reserve the term "ideal cut" for diamonds that have depth and table percentages that fall within the AGS 0-cut parameters, regardless of what certification. Since the GIA and most grading laboratories other than the AGS do not provide all the cut parameters on their certifications, it is often necessary to get a Sarin report on the diamond. A Sarin report measures parameters other than depth and table percentages and assesses where they fall within the AGS cut grades.

4C's : Color

Diamond color has a significant impact on its value. The color scale ranges from D to Z, from colorless to light yellow, respectively. To ensure the highest quality diamonds for your selection TOG carries diamonds in the color range from D-L only.

The farther from colorless that a diamond's grade is, the less rare and therefore less valuable it is. When buying a diamond, take into consideration that it is often very difficult to detect the difference between a colorless diamond (D-F) and a near colorless diamond (G-H), especially when it is mounted in jewelry. Diamonds with a J-Z color grade usually have yellow shading that can be detected by the naked eye, however, a well cut stone with good proportions will still release the brilliance and fire of a lower colored diamond, dispersing light in such a way so as to create a beautiful stone.

Diamonds also come in a range of natural fancy tones, such as blue, pink, green, and red. Such diamonds have so much color that they are not graded on the normal scale D-Z. Believe it or not, these fancy diamonds are particularly rare, and like their colorless counterparts, can also come attached to a high price tag. Bear in mind that color does not have an exclusive impact on a diamond's value. The value of a stone is affected by a combination of qualities including shape, clarity, cut, and carat weight, as well as its color.

D: Absolutely colorless. The highest color grade, which is extremely rare.

E: Colorless. Minimal traces of color that can only detected by an expert gemologist. Also, a very rare diamond.

F: Colorless. Slight color, which can only be detected by an expert gemologist, but still considered a "colorless" grade.

G-I: Near-colorless. Color noticeable when compared to diamonds of better grades, but these grades offer excellent value. A TOG excellent value.

J-K: Near-colorless. Color slightly detectable.

L-N: Noticeable to the untrained eye.

O-S: Not carried at TOG.

T-Z: Not carried at TOG.

Fluorescence

A bluish glow that comes from a stone exposed to ultraviolet light. The effect of fluorescence depends on the combination of the color of the stone in question and the strength of the fluorescence. Faint fluorescence has very little effect on a stone of any color. Medium blue fluorescence and strong blue fluorescence can have a positive effect on stones of low color (J or worse). The fluorescence actually has the effect of making the stone look closer to near colorless. On stones of high color (D-G), strong or medium blue fluorescence can make the stone look milky instead of colorless or near colorless.

TOG Best Value: Color

For the best value in diamond color, TOG only carries diamonds in the color range of D-K. Diamonds with a higher color grade appear whiter. The whiter the diamond, more light is able to pass through it, making it sparkle and shine. Diamonds with a color grade of K and higher are near-colorless or colorless, and are recommend best value, since their color is undetectable to the untrained and unaided eye.

4C's : Clarity

When gemologists inspect diamonds for overall quality, they must painstakingly determine the clarity of the diamond. Using a 10x magnification loupe, gemologists determine the size, type, and position of the imperfections.

Members of the industry refer to these imperfections in diamond clarity as "inclusions." Gemologists then put the stone into one of the following classifications based on the results of their inspection:

Within the VVS, VS, and SI classifications there are additional gradations denoted by a number 1 or 2. For the included class, the subdivisions are denoted with a number from 1 to 3. Because most diamonds have flaws, flawless diamonds and nearly flawless diamonds (clarity between FL and VVS2) are considered particularly rare and are consequently particularly pricey. Bear in mind that an ideal cut diamond will optimize the use of light, creating fire and brilliance. Inclusions can hinder how the light reflects, lessening the brilliance and prismatic effect of color in a diamond.

FL	Flawless: No internal flaws. Very rare and very expensive.
IF	Internally Flawless: No internal flaws. Also very rare and very expensive.
VVS1-VVS2	Very, Very Slightly Included: Extremely difficult to see inclusions under 10x magnification. Rare and expensive.
VS1-VS2	Very Slightly Included: Inclusions are not visible to the unaided eye. High quality.
SI1-SI2	Slightly Included: Inclusions are visible under 10x magnification. Good quality.
I1-I2-I3	Included: Inclusions and flaws visible to the naked eye.

TOG Best Value: Clarity

For the best clarity value, TOG recommends that you choose a clear, "clean", or "eye-clean" diamond. An eye-clean diamond has no inclusions or blemishes visible to the naked eye. To ensure the highest clarity diamonds TOG only carries diamonds with a clarity grading of: FL, IF, VVS1-VVS2, VS1-VS2, and SI1-SI2. TOG does not carry diamonds with I1, I2 or I3 clarity grades.

4C's : Carat Weight

A carat is the unit of measurement which the jewelry industry uses to weigh diamonds. One carat is equal to .20 grams. Often diamond weight is declared in points. One carat is equal to 100 points. Thus, a .75 carat diamond is equivalent to 75 points.

Do not buy into the belief that the larger the carat weight, the more valuable the diamond. While this can be true, it is not necessarily so. Keep in mind that retail and wholesale diamond dealers take into account a stone's color, clarity, and cut, as well as carat weight when pricing a diamond and often their pricing is subjective. For that reason, it is important for every potential diamond buyer to prioritize each of the aforementioned characteristics when considering a stone. Remember that choosing a diamond is not an exact science.

TOG Best Value: Carat

When selecting the best carat weight, take into consideration her taste & style, her finger size, the type of band or setting, and your budget.

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