Up to 35% of all diamonds in the world emit a glow when subjected to ultraviolet light. This glow is called fluorescence.
When we refer to stone's fluorescence, we mean medium to very strong fluorescence. Faint fluorescence is not considered to be detrimental to the value of the diamond.
There is little science to back up claims that fluorescent diamonds are inferior stones. Fluorescence commonly occurs in only 25-35% of all diamonds. According to GIA, fewer than 0.2% of the fluorescent diamonds appear "hazy or oily," so the ill effect is incredibly rare.
A fluorescent stone is the cashmere sweater with the red dot of the diamond world - the regret lingers long after the joy of getting a bargain is forgotten.
What is fluorescence
Fluorescence is an ability of a diamond to emit a glow when subjected to ultraviolet light, just like Fido's stains do.
According to GIA research, up to 35% of all diamonds in the world fluoresce.
Fluorescence intensity depends on the UV light strength and ambiance lighting. Disco lighting, fluorescent bulbs, and natural sunlight all have a UV component that triggers the glow.
According to GIA, fewer than 0.2% of the fluorescent diamonds are "hazy or oily" as a result of the fluorescence, so that phenomenon is incredibly rare.
The fluorescence grade "Negligible" used by AGS (but who cares what AGS calls it, GIA is the gold standard) is the same as "None" by GIA. It refers to diamonds that refuse to glow under the blacklight.
Is there any good reason to buy a fluorescent stone?
Strong blue fluorescence is thought to enhance a diamond's appearance in I to K color range, but this is highly debatable.
Colorless diamonds with strong fluorescence are sold at a steep discount even when they appear perfectly clear, so you get a bargain.
Buy a fluorescent stone when:
In countries like Vietnam, Malaysia, Indonesia, near colorless to faint yellow diamonds with fluorescence are more desirable.