Diamonds are graded on a scale of D through Z following the grading system used by the Gemological Institute of America (GIA). The highest grade, D, is the purest white color, with each subsequent letter corresponding to a slightly darker shade, down to Z, the lowest color grade on the scale. Color in a diamond refers to the body tone of the diamond.
A diamond’s clarity is determined by taking into account the number, size, placement, color, and nature of any internals or external surface flaws. Inclusions are nature’s birthmarks. However, the fewer there are, the rarer and more valuable the diamonds are.
Diamonds are cut to an exact mathematical formula. In grading, cut evaluates the cutters skill in the fashioning of the diamond. Diamonds have a unique ability to manipulate light efficiently. This unique ability can be released and maximized only by cutting and polishing the diamond to an extremely high level of accuracy.
The carat refers to the weight of the diamond. Historically, it represented the weight of a carob seed; thus, the term carat. In more exact measurements, 5 carats is equal to 1 gram. Therefore, two diamonds of the same weight can appear quite different in appearance.
Learn more: Gemological Institute of America (GIA)
The GIA developed the “4 Cs.” If you’re interested in more in depth graphic information, we’ve included their 4 minute video on How to Choose a Diamond. Click on the “Play Video” icon below.