Color is the amount of yellow tint a diamond displays. The very best color for a diamond is no color at all. The reason is simple: absence of color means no conflict to dim the beauty of the natural light entering the stone and breaking into its spectral elements – brilliant reds, blues, and violets.
Diamond Color grades are letters of the alphabet starting with “D” and ending with “Z”. D through F are all considered “colorless”, G-J are “white” or “near colorless”. In K-L stones, you can usually see yellow tint face up, and below L you can see a lot of tint. Here is the entire GIA color grading scale:
The only way to grade diamond color is to have the diamond loose from the mounting and to compare it to a color master grading diamond. A color master is a special diamond from GIA certified for use as a standard in color grading. A good store will have a full set (usually 5-7 diamonds) of color masters and be able to show you your diamond next to the master it matches.
Rule: Ask to see your diamond loose next to the appropriate color master diamond if you would like to verify its color.
Note: Certified color-master grading diamonds have to be natural diamonds and cannot be diamond simulants (CZ’s).
Diamond color actually measures the diamond’s lack of color. The diamond color scale starts at D (colorless) through Z (the most color, typically a light yellow, brown, or gray color). The closer a diamond is to colorless, the higher the value, with the exception of fancy color diamonds; yellows, pinks, blues, etc. which have their own color range.
Most diamonds you’ll see in jewelry stores range from colorless to near-colorless, usually with a tint of yellow or brown.