Diamonds with Fluorescence Can Improve or Reduce the Grace of Appearance
1990: Diamonds with Fluorescence Evidence Strong Reactions
William E. Boyajian, President of the Gemological Institute of America sums up an extensive research paper published recently in Gems & Gemology that deals with the effects of fluorescence on diamonds.
Mr. Boyajian states that: "The study challenges the perception held by many in the trade that UV fluorescence generally has a negative effect on the overall appearance of a diamond. In fact, the results support the age-old belief that strong or even very strong blue fluorescence can improve appearance rather than detract from it, especially in diamonds with faint yellow body color. This result is consistent with the slightly higher "asking" prices reported for these stones."
Prior to the popularization of certificates, there was actually a widespread preference for stones with fluorescence. They were once called "river" diamonds, since often such diamonds were actually found in riverbeds. They were also dubbed "blue-white" diamonds, and long time diamantaires can recall a time when many buyers would insist on diamonds with a bluish tint or fluorescence.
This preference began to wane gradually following a decision by the Federal Trade Commission which outlawed the use of the term "blue-white." The move came in reaction to misuse of the term, but it apparently had the unintended affect of casting a suspicious shadow over any and all diamonds evidencing bluish fluorescence.
The reality is that an I-colored diamond with fluorescence may appear from a top view as white as a G or H color — which enhance its beauty.
On the other hand, a D-colored diamond with fluorescence will show some bluishness which may occasionally detract from its luster if the fluorescence is so strong as to make the stone appear hazy.