Diamonds come in every color of the spectrum, but the most popular are colorless. Truly colorless, pure white diamonds are extremely rare and, therefore, the most costly. Laboratories, like the Gemological Institute of America (GIA), grade stones according to how far they deviate from the purest white as one of the diamond 4Cs.
The best way to see the true color of a diamond is by looking at it against a white surface. Colorless stones are graded D, E or F. All three grades are considered colorless but with slightly decreasing transparency. Color grading continues down through the alphabet, with each letter designating a slight darker or warmer tint.
Diamonds also come in a spectrum of majestic colors, from red and canary yellow to blue, green and purple. These colorful diamonds, known as fancies, are valued for their depth of color, just as white diamonds are valued for their lack of color. Therefore, fancy color diamonds are graded in order of increasing intensity from Faint, Very Light, Light, Fancy Light, Fancy, Fancy Intense, Fancy Vivid, Fancy Dark and Fancy Deep.
Diamond color grades are determined by professionals under ideal circumstances, a situation seldom duplicated outside of a laboratory. Choose a diamond based on its appeal to you, rather than on a technical color scale.
A Note on Color Grading
It is important to remember that color is a range. Think of a diamond color grade as your age. If you’re 34 years old, your 34th birthday may have been yesterday, or your 35th birthday may be next month. But when someone asks your age, you simply tell them you’re 34. It works the same way with color grading. For example, a diamond with a G color grade could, in fact, be very close to an F or to an H.
Information courtesy of Jewelers of America.