Determining diamond color is a very subtle art. So many diamonds look perfectly colorless to the naked eye, which makes it hard to distinguish between the varying degrees of coloration. Nevertheless, diamond color is an important factor in determining the value of a diamond. These tiny variations have quite an impact on the overall appearance of the diamond.
The Gemological Institute of America uses a scale that goes from D –. Z to determine diamond color. A D-colored diamond is considered colorless. A Z-colored diamond is considered light yellow. For the most part, the closer a diamond is to a rating of D, the more it's worth. The reason for this has to do with the purity of the light that's reflected from the diamond. A colorless diamond will reflect all the shades of whole, white light equally. Acting like a prism, it'll produce dazzling colors as it turns in the light. A yellow diamond favors the yellow wavelengths of light. Doesn’t give as brilliantly lustrous an appearance as it’s colorless cousins.
There are diamonds that are colored more intensely than the D-Z scale accounts for. These are called fancy color diamonds. These are diamonds of any color (did you know that diamonds come in every color?) that have very high color saturation levels. These are of higher value than diamonds in the lower alphabet range of the D-Z system.
Diamond color affects the price quite substantially. For a 1 carat diamond with a clarity rating of VS1 starting at a color rating of K, the color breakdown would look like this: Moving the color rating up to H will add approximately $1,700 per carat to the price of a diamond. From H to F, the price increase is another $1,100 per carat. From F up to D (the highest rating, colorless) the price increase would be an additional $900 per carat.
A quick tip for men who are shopping for diamonds for their future spouses. Take a woman you can trust with you. For the most part, women are more sensitive to the subtle differences in color than men are. It’s not a rule. It does tend to hold true in most situations.