Diamond Fluorescence

Fluorescence means that a diamond will glow usually in blue under UV light when illuminated. The effect is like a white shirt at a disco party, it glows. Fluorescence can range from faint to very strong and can make a yellowish diamond look white or colourless. When the diamond is not under UV light the fluorescence stops immediately, but some stones continue to phosphoresce for a little while.

Fluorescence results due to visible light being emitted by electrons, occurring when a diamond is excited by a higher energy source, for example UV light. Some diamonds which have strong fluorescence appear oily or cloudy, which is not good. However a study performed by GIA showed that these diamonds are very rare; they were unable to find enough cloudy stones from the 26,010 sample they used.