Why diamonds glow?
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 infrequent.
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” due to the fluorescence, so that phenomenon is infrequent. 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 the I to K color range, but this is highly debatable. Because of that off-white diamonds with strong fluorescence are sold at a steep discount even when they appear clear, so you get a bargain.
Buy a fluorescent stone when:
- You can’t afford the diamond you want
- It is the only option available
- You are mesmerized by the glow effect
- The center stone is I-J color as graded by GIA
- The stone is tiny
- The stone is not certified
- You believe in the magical properties of fluorescent diamonds.
In countries like Vietnam, Malaysia, Indonesia, near colorless to faint yellow diamonds with fluorescence are more desirable.