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Even though they are transparent, most diamonds contain some hint of color. This is caused by the presence of nitrogen in the earth where they formed. Diamond color grading is done on a scale of D to Z.

D is ‘icy-white.’ These diamonds are the most colorless and most rare, so they are considered most valuable. There are 23 descending grades, so the increasing hints of color are very slight. The average person cannot distinguish between several color grades. D, E and F diamonds are all considered colorless to normal vision. G, H, I and J are called near-colorless but still considered to be in the white range. K through Z are faint yellow to yellowish or brownish. A diamond with more color than a Z is a ‘fancy colored diamond’ and could be a different color like pink or blue. These ‘fancy colors’ are not graded on the same scale.

grading report from the ags or gia

Color and the influence of CUT

The shape of a diamond influences the amount of color people may see in it. A round brilliant is the most efficient shape for returning light and will show less apparent color than a mixed cut like a princess, or a step cut like an emerald or asscher. But most important is how well the diamond was cut.
Diamonds are graded in the face-down position and viewed for color from the side. This is because great light return in a diamond can ‘mask’ color, especially in round brilliants. Extremely well-cut diamonds may appear more colorless in the face-up position than the grade they received at the lab due to superior light return. For instance, a diamond that was graded H in the side position can ‘face-up’ like a G or an F, but only if it was cut extremely well.
Whiteflash first sold only diamonds in the D-I range, but our commitment to cut quality resulted in the majority of our near-colorless diamonds to face up several grades better. As a result we are now selling colors as low as K, to the delight of many consumers.

Color and Sensitivity

Some people are more color-sensitive than others. One person may see color in a diamond that appears to have no color to someone else. Even if you have great sensitivity to color you may have different preferences than others. The icy whiteness of a D may appeal to one person, while the warmer look of a J appeals to another. A third person may not see any difference between the two.

Color and Settings

Remember that diamonds absorb the color of their surroundings, so it’s best to judge them against a white background. Once mounted a diamond will show less color than it did loose. Remember that the choice of setting may influence your diamond’s color. If you choose a gold setting and have a colorless diamond that diamond may absorb and reflect back some of the setting color. There are many different combinations and no single one is for everyone. Ultimately the choices are determined by personal preference and sensitivity.

Color can’t be judged in photos or on monitors.

Consider which lab assigned the grade.
Wear a white, gray or black top when shopping.
Judge color against a white background.
View the diamond unmounted.
View the diamond from the side looking for tint.
Compare side versus face up appearance.
With “very strong” fluorescence look for an oily or milky appearance.
Consider your diamond’s color when choosing your setting.
See the diamond in the proposed mounting before purchase.

Clarity

Clarity Grading

F and IF mean the diamond is Flawless or Internally Flawless when examined by a trained professional under 10 power magnification. Such diamonds are very rare and are costly.
VVS1 and VVS2 stand for Very Very Slight inclusions. This means the professional found it very difficult to see minute inclusions under magnification. There is practically no chance an observer will see such inclusions with the naked eye.
VS1 and VS2 stand for Very Slight inclusions. VS1 is difficult for a professional to see with 10 power magnification. VS2 is easier to see, still under magnification. It is very unlikely that an observer will see VS inclusions with the naked eye.
SI1 and SI2 stand for Slightly Included. This means a professional easily saw inclusions with 10 power magnification, but may or may not be able to see them with the naked eye. Whether or not a diamond is “eye-clean” to an observer will be discussed in a moment.
I1, I2 and I3 stand for Included. These inclusions are easily seen with magnification and are also visible to the naked eye.
Clarity and Grading Standards
As with color, you should always consider where the diamond was graded. Grading is subjective and some laboratories give easier grades than others. In the United States the GIA and AGS are widely considered the strongest laboratories.

Clarity Summary

Clarity is quite simple. If you don’t want inclusions, a grade like VS or VVS will practically guarantee that you will never see one. If you want to find an eye-clean SI1 or SI2 diamond you will need to work with an expert you can trust to find one that meets your expectations.

Carat

Carat Weight

The weight of a diamond is expressed in carats. This term comes from ancient times when gems were weighed against the carob bean. One carat is equal to 200 milligrams, or one fifth of a gram.
Carat weight is sometimes expressed in points. One point equals 1/100th of a carat, so 25 points is equal to a quarter of carat and 50 points is equal to half of a carat. Grains of rice were also used. 4 grains of rice were equal to a carob bean. That’s why people sometimes call a quarter carat diamond a one grainer.

Carat Weight and CUT:

Carat weight is not the same thing as size. As diamonds increase in weight their apparent size becomes less predictable. Diamonds cut too shallow may appear larger than they should, while diamonds cut too deep may look smaller. Too shallow and too deep are both undesirable. In this example bigger is not better.

proper spread

You should always use millimeter measurements and consider girdle thickness when judging proper spread for carat weight.

diameter guide for rounds

Apparent Size

The 4C's of Diamonds

The cut of a diamond refers to its proportions. It is one of the most important factors to be considered while choosing your diamond. It is an aspect which is directly influenced by man. The other three are influenced totally by nature.
The cut of a diamond should not be confused with its shape. Shapes are cut from the original rough diamond, and whatever the shape, a well-cut diamond is always better able to reflect light.
Diamonds are usually cut with 58 facets, or separate flat surfaces. These facets are placed at precise angles to each other. This relationship is designed to maximize the amount of light reflected through the diamond and to increase its beauty.
Rough stones can be cut to their maximum weight and monetary value but loses some "brilliance and "sparkle". Similarly rough stones can also be cut into the most beautiful stone, despite heavy weight loss and lowered monetary value.