The most important thing to know about color when it comes to diamonds is, in general, the less color a diamond has, the more valuable it is, all other factors being equal. Diamonds are found in nature in a wide range of colors, from completely colorless (the most desirable trait) to slightly yellow, to brown. So-called a fancy color diamonds TM come in more intense colors, like yellow and blue, but these are not graded on the same scale.
The color grading system for diamonds uses the letters of the alphabet from D through Z, with a TM being the most colorless and therefore the rarest and most valuable, and a having the least color within the normal range, and being the least valuable, all other factors being equal. A diamond's color is determined by looking at it under controlled lighting and comparing them to the Gemological Institute of America's color scale, which is based on a set of diamonds of known color. Here is a diagram showing how a diamond,s color is graded:
make up a small but exotic part of the diamond industry. These diamonds include red, blue, green and pink as well as the stronger yellows. Red, Pink and green are the rarest fancy colors. They also come in combinations such as orange/yellow or gray /blue. These stones are expensive and quite rare. A fancy red one-carat stone can run up to $1,000,000, depending upon the beauty of the stone.