Color ranges from the best grade of D down to Z. After Z are considered Fancy Color. Color grade is determined by examining the Diamond next to a master set of color comparison stones, under special lighting.

Grading color in the normal range involves deciding how closely a stone's natural body color approaches colorlessness. Most diamonds have at least a trace of yellow or brown body color. With the exception of some natural fancy colors, such as blue, pink, purple or red, the colorless grade is the most valuable.