A colorless diamond is the ideal color and is referred to as the whiteness of a diamond.
The diamond’s color-grading chart begins with D and ends with Z. While D refers to the absence of color in a diamond, Z refers to the presence of color (faint yellow) in a diamond.
Unlike many beautiful things in nature, the absence of color in a diamond is a symbol of purity and is considered the ideal gem. A diamond’s color grade is based on its lack of color, the less color a diamond has, the higher the color grade.
By selecting a diamond that is considerably colorless or white (especially if it was set in white metal), one needs to select a diamond color grade of F or better. Choosing a diamond with a near colorless grade of G, H, I, or J will have a slight presence of color but will give you a better value for your dollar.
Color Grade sheet
D: Absolutely colorless: The highest grade of color
E-F: Colorless: An expert gemologist can detect minute traces of color.
G-J: Near colorless: Color difficult to detect by the naked eye, unless compared side by side against diamonds of higher grade.
K-M: Faint Color: Has a slight yellow hue.
N-R: Noticeable color: Diamonds in this color range tend to have a yellow hue
S-Z: Very Noticeable Color: The diamond has an apparent yellow hue