The 4 C's When selecting a diamond, it is important to have an understanding of the 4 C's. But what are the 4 C's and what in the world do they actually mean? Here is a brief explanation of cut, carat weight, color, clarity, and what they mean when you are picking a diamond. Cut Carat Color Clarity   The color grade of a diamond refers to the degree of color present in the diamond. Most diamonds have at least a trace of yellow, brown or gray body color. With the exception of a few fancy colored diamonds in deep shades of blue, red, purple and pink, the colorless grade of diamonds is the most rare. The closer a diamond is to colorless, the more valuable it is. The Gemological Institute of America (GIA) created an alphabetic color grading scale for diamonds. Diamonds with the least amount of color are classified as D. Going down the scale, the diamonds with the most color given a Z rating. Small changes in color can result in large changes in the price. Diamonds graded D to G in color, should generally be set in white gold or platinum to enhance the stone's beauty, while stones in H to L in color, should be set in yellow gold for a more colorless feel.