What is color? By definition, it is a phenomenon of light or visual perception by which one can distinguish between otherwise identical objects. Of course this is an over-simplification, but it is how we will consider color as it relates to diamonds. Color and color grading is a very large part of the process of the valuation of a diamond, so it must be well-understood for success in the diamond business. For the most part, a better sense of color as it pertains to diamonds, would be the lack of it. As a general rule, the less color (or the closer to colorless), the more valuable the diamond. The exceptions are the fancy colors, where some stones can be extremely rare and valuable.