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 . . . While the apparent benefits of blue fluorescence are less obvious in colorless to very near-colorless diamonds, they still were evident in the study. This should bring into question the trade’s lower bid prices for moderate to highly fluorescent diamonds in the better colors.
Before diamond grading reports became so popular, there was a widespread preference in the trade for stones with fluorescence. These diamonds were called “blue-white” diamonds, and long time diamantaires can recall a time when many buyers would insist on diamonds with fluorescence. The preference began to decline after the FTC outlawed the misuse of the term “blue-white”.
Harry Oppenheimer was the son of the founder of the company that would become the most successful cartel of the twentieth century – De Beers Consolidated Mines, Ltd. The South African company incorporated in 1888, during the burgeoning local diamond rush. At its formation and over the ensuing years, De Beers would successfully acquire countless interests in diamond mines and production facilities throughout the world. Diamond fluorescence indicates that the diamond emits light when exposed to Ultraviolet light (long-wave radiation) or sunlight. Diamonds exhibit fluorescence when small amounts of the element boron are present in the stone. Blue is the most common color of fluorescence, but other colors are also possible. The majority of diamonds don’t exhibit fluorescence.
The impact of fluorescence has long been debated; in the Winter 1997 issue of GIA’s Gems & Gemology, William E. Boyajian, President of the Gemological Institute of America, had the following to say on the topic: Opinions of even the most experienced trades people vary widely. With great conviction, some say that blue fluorescence of different strengths typically enhances a diamond’s overall appearance. Others, as convincingly, say that it has a negative effect.
To address this controversy, researchers at the GIA Gem Trade Laboratory conducted an experiment on the effects of long-wave ultraviolet radiation on the color appearance and transparency of gem diamonds . . . [The findings of the] study challenge the perception held by many in the trade that UV fluorescence generally has a negative effect on the overall appearance of a diamond.