The Gemological Institute of America (GIA) has created literature which will help elucidate the phenomenon of ultraviolet fluorescence in diamonds, more effectively in its grading reports. The information will describe fluorescence and its properties, and will appear in every GIA Diamond Grading Report and Diamond Dossier® that carries a diamond fluorescence description of medium or stronger.

There is a four-colour insert which addresses the most frequently asked questions about fluorescence, explains its properties and includes comparison images of diamonds in both natural and UV light to illustrate varying intensities of fluorescence. Until recently, for over 50 years, GIA has indicated the presence of diamond fluorescence on its diamond grading reports, but as an identification characteristic only – not a grade, explained Thomas M. Moses, GIA’s senior vice president of Laboratory and Research. The five terms GIA uses to classify the intensity of the fluorescence are: None, Faint, Medium, Strong, and Very Strong.

“Some diamonds show fluorescence and some don’t,” said Moses. He further added “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 colour, which most often stops when the energy source causing it is removed.”

“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,” he said.