Fluorescence is a famous phenomenon that diamond enthusiasts the world over are familiar with. What an alarming number of people in the diamond industry are not sure about though, is how it affects the pricing of a diamond.
Diamond fluorescence is the distinct glow that you sometimes see coming out of a stone, which is somehow emitting light that it normally does not. Most diamonds that have this property, and they emit light under UV light that can come from sunlight as well as fluorescent lamps. The stone emits a bluish light in most cases, but there are ones, that give out orangy or yellow light. When you remove the UV source, the fluorescence stops. Only about a third of diamonds fluoresce, and to varying degrees.
Diamond Fluorescence Grades
Diamond fluorescence is considered an indentifying trait by GIA. While not the same kind of grading factor as one of the 4 C’s, fluorescence does get mentioned on a diamond report, along with its intensity.
Can Fluorescence Cause a Yellow Diamond to Look Whiter?
Blue fluorescence is considered as one of the things that improve the appearance of a diamond, especially if it has I to M grade color. A faint yellowish stone can look closer to colorless when placed under UV light, and that includes sunlight as well. Strong-to-medium bluish fluorescence can noticeably raise the visual appeal, and consequently also the price-per-carat. However, for D to H colors, bluish fluorescence is visually detrimental, causing what many see as an oily appearance, especially if the fluorescence is intense.
Can the Average Customer Distinguish Diamonds with and without Fluorescence?
GIA has screened tens of thousands of diamonds in each color grade, and studied the effects that blue fluorescence has on them. They found that the average observer would generally not spot differences in fluorescent property between otherwise similar stones, placed face-up. Experienced observers too would need a closer look to arrive at a view that they agreed on with their peers.
Is Fluorescence Good?
Fluorescence does not really affect the beauty of a diamond, and as such is neither good nor bad. If you perceive it, there is a chance of you liking it, as well as a chance of the opposite happening. If you want blue fluorescence in your stone, make sure you look at several stones under UV light so that you can be sure how each looks in that kind of lighting.