Effective immediately, the Gemological Institute of America (GIA) will include a description of a diamond’s ultraviolet fluorescence in its GIA Diamond Grading Reports and Diamond Dossiers. The Institute will use in their newly revised diamond grading reports to help better educate the public on this “common, but little understood phenomenon in diamonds,” the Institute said in a recent press release.
A separate, four-color insert chart will explain the properties of a diamond’s fluorescence in consumer-friendly terms and includes comparison images of diamonds in both natural and UV light to illustrate varying intensities of fluorescence. The five terms GIA uses to classify the intensity of the fluorescence are: None, Faint, Medium, Strong, and Very Strong.
A sample fluorescence chart.
“Some diamonds show fluorescence and some don’t,” said Thomas Moses, GIA’s senior vice president of Laboratory and Research. “Fluorescence is the emission of visible light by a diamond when it is stimulated by invisible ultraviolet (UV) rays. It is a common characteristic of diamonds. The diamond simply glows under the UV lights, usually a blue color, which most often stops when the energy source causing it is removed.”
For more than 50 years, GIA has indicated the presence of diamond fluorescence on its diamond grading reports, but described it on the report as an “identification characteristic only – not a grade,” Moses said.
“This insert will help the public better understand diamonds in general, which gives them more confidence and knowledge when making a decision about a diamond,” Moses added.
GIA has additional information on fluorescence on its website, including a scientific article, “A Contribution to Understanding Blue Fluorescence on the Appearance of Diamonds,” by Thomas M. Moses, Ilene M. Reinitz, Mary L. Johnson, John M. King and James E. Shigley, which appeared in the Winter 1997 issue of GIA’s Gems & Gemology.