What is Diamond Fluorescence?
Diamond fluorescence is the effect that ultraviolet light has on a diamond. Under UV rays, fluorescence is the visible light emitted by the diamond when it is exposed to UV rays. Although relevant to diamond grading, diamond fluorescence has no bearing on most people’s choice when they set out to buy a diamond.
According to the Gemological Institute of America (GIA), fluorescence in a grading report refers to the “strength, or intensity, of the diamond’s reaction to long-wave UV, which is an essential component of daylight.” However, for most diamonds, the strength of fluorescence has no widely noticeable effect on appearance, and the average person cannot distinct between a diamond with fluorescence and a diamond without it. Moreover, fluorescence has no bearing on the structural integrity of a diamond; in other words, fluorescence isn’t “bad” for a diamond, and does not weaken it in any way.
It is only rarely that fluorescence affects a diamond’s appearance. According to the GIA, less than 35% of all diamonds submitted for grading have some degree of fluorescence, and only 10% of those show strengths of fluorescence that may affect appearance. In more than 95% of the diamonds that exhibit fluorescence, the visible color is blue, and rarely, the reaction to fluorescence is yellow, white or another color.