The color of a stone is influenced by minute amounts of trace elements other than carbon that were present during the formative process over years within the earth’s core. In actuality, a diamond's color grade is determined by its "lack of color". The "whiter" the diamond, the higher color grade it receives.
Diamond color ranges from colorless to yellow brown, onto fancy colors such as blue, green, pink, etc. Whilst color grading, the saturation of the color of diamonds is compared to master stones using D65 lighting and neutral grey surroundings.
The grading scale for regular colors is as follows:
D – exceptional white +
E – exceptional white
F – rare white +
G – rare white
H – white
I - J – slightly tinted white
K - L – tinted white
M - Z – tinted color