The majority of natural diamonds fall within a color range that runs from colorless (sometimes called white) to near-colorless, and then to lightly yellowish or brownish.
The slight variations that occur in a diamond’s color form the basis of a generally accepted color grading system, first introduced by the Gemological Institute of America (GIA), which uses the letters of the alphabet. In this system D is the highest grade, and it is assigned to a completely colorless or white diamond – a rare phenomenon.
Near-colorless diamonds are graded with the letters E and F. The most common color grades encountered by diamond consumers run from the color grade G through the color grade M. Diamonds that display a slight yellowish or brownish hue receive the color grades K, L or M. The color grades N, O, P, Q and R represent stones with a progressively light yellowish tint, while the grades S down to Z represent diamond that show an increasingly yellowish or brownish hue.
When diamonds are of a truly vivid color, for instance a lively “canary” yellow or a distinctive pink, they are defined as fancy colored diamonds. Here, the alphabetical color scale does not apply and they generally are described according to their hue, and the intensity of the color.