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

E: Colorless. An expert gemologist can detect only slight traces of color. A rare diamond.

F: Colorless. Slight color detected by an expert gemologist, but still considered a "colorless" grade. A high-quality diamond.

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

I-J: Near- colorless. Color slightly detectable. An excellent value.

K-M: Not carried

N-Z: Not carried.