A diamond's color is graded on an alphabetical scale from D-Z to describe how much or how little color a diamond possesses. The best quality diamonds and the most valuable ones are completely colorless. Very few diamonds reach this standard.

Nuances between color grades are very hard to distinguish. Subtle differences are usually judged through the pavilion side of stone using a set of "master stones" for comparison. While many diamonds appear colorless, or white, they may actually have subtle yellow or brown tones that can be detected when comparing diamonds side by side. Diamonds were formed under intense heat and pressure, and traces of other elements may have been incorporated into their atomic structure accounting for the variances in color. A single change in color grade can significantly affect a diamond's value. Although the presence of color makes a diamond less rare and valuable, some diamonds come out of the ground in vivid 'fancy" colors -- well-defined reds, blues, pinks, greens, and bright yellows. These are highly prized and extremely rare.

FLUORESCENCE: A diamond's fluorescence is a tricky thing. To put it simply, a diamond's fluorescence is its glow under the influence of ultraviolet (UV) light. With the unaided eye, it is very hard to see when not in the proper environment. For example, in simple sunlight, UV light is abundantly present, but then again, so is every other spectrum of light, thus drowning out the glow. Technically, it is visible, but only the trained eye could see it after a short while of looking. Under halogen and fluorescent lights, there simply aren't any (or very little) UV rays emitted, making the stone look as wonderful as can be, just without any fluorescence. However, under a special light source designated to send out only UV light, a diamond will show its "true colors." A UV light, aimed at a diamond, will bounce back only if the stone has fluorescence. The stronger the fluorescence, the brighter the UV light bounces back. Almost every case of fluorescence results in a blue tone, but there is always the exception to the rule, resulting in different tones. Fluorescence is a thoroughly debated topic in the diamond industry.

There are people who like it and there are those who don't. Some enjoy it as a little extra surprise held deep within the stone, and others claim that it takes away from the diamond's natural brilliance. A diamond's fluorescence is a natural phenomenon, just not always appreciated. Fluorescence indicates if the stone reacts to UV light. It is graded as faint, moderate, strong or very strong, and may be followed by a color such as blue or yellow. A diamond with fluorescence strong yellow is less valuable because it may appear yellowish in daylight or fluorescent lighting. The presence of blue fluorescence will not detract from a diamond, and will in some cases add value because the stone will appear whiter in daylight or fluorescent lighting. However, an ideal-colored diamond will exhibit none to very faint fluorescence. Strong or intense fluorescence will decrease the value of a diamond.