Gemology. Volume 33 Issue 4 A Contribution to Understanding the Effect of Blue Fluorescence on the Appearance of Diamonds Thomas M. Moses, Ilene M. Reinitz, Mary L. Johnson, John M. King, and James E. Shigley The presence of fluorescence in diamonds has been for some time a subject of controversy in the trade. GIA Gem Trade Laboratory (GIA GTL) researchers designed a visual experiment to study the effect of fluorescence on diamond appearance. 'Observers in this study found blue fluorescence to have, at best, a subtle effect on color appearance and transparency,' said Thomas Moses, GIA GTL vice president of identification. The study's results indicated that average observers, like those in the jewelry buying public, saw no systematic differences in color or transparency with fluorescence. In general, the strength of fluorescence had no perceptible effect on the color appearance of diamonds viewed table-down. In the table-up position, diamonds with strong fluorescence were reported to have a better color appearance than those with less fluorescence. This study challenges the industry notionthat fluorescence has a negative effect on better-color diamonds. GIA's result supports considering each individual diamond on its own visual merits. The Impact of Fluorescence in Diamonds: A Different Research Perspective William E. Boyajian The effect of ultraviolet fluorescence on diamond appearance has been hotly debated for at least the past decade. 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 study's 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. The science of gemology is not just about spectral analysis. It is also about dispelling (or, in some cases, confirming) beliefs that have been perpetuated over the years, and about separating bias and tradition from reality in the gem industry Gemology. Volume 33 Issue 4 A Contribution to Understanding the Effect of Blue Fluorescence on the Appearance of Diamonds Thomas M. Moses, Ilene M. Reinitz, Mary L. Johnson, John M. King, and James E. Shigley The presence of fluorescence in diamonds has been for some time a subject of controversy in the trade. GIA Gem Trade Laboratory (GIA GTL) researchers designed a visual experiment to study the effect of fluorescence on diamond appearance. 'Observers in this study found blue fluorescence to have, at best, a subtle effect on color appearance and transparency,' said Thomas Moses, GIA GTL vice president of identification. The study's results indicated that average observers, like those in the jewelry buying public, saw no systematic differences in color or transparency with fluorescence. In general, the strength of fluorescence had no perceptible effect on the color appearance of diamonds viewed table-down. In the table-up position, diamonds with strong fluorescence were reported to have a better color appearance than those with less fluorescence. This study challenges the industry notionthat fluorescence has a negative effect on better-color diamonds. GIA's result supports considering each individual diamond on its own visual merits. The Impact of Fluorescence in Diamonds: A Different Research Perspective William E. Boyajian The effect of ultraviolet fluorescence on diamond appearance has been hotly debated for at least the past decade. 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 study's 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. The science of gemology is not just about spectral analysis. It is also about dispelling (or, in some cases, confirming) beliefs that have been perpetuated over the years, and about separating bias and tradition from reality in the gem industry
| 
