Diamond Fluorescence​

What is diamond fluorescence?

Fluorescence is the glow that can be seen sometimes when an object emits visible light. When some diamonds are exposed to ultraviolet (UV) rays from sources like the sun and fluorescent lamps, they fluoresce to some degree emitting a bluish light or more rarely, a yellow or orangy light. These diamonds stop fluorescing once the UV light source is removed.

Even though some diamonds fluoresce when exposed to UV light sources, the overall diamond fluorescence should not be a major factor in the purchase of a diamond since its effects are negligible.


Diamonds under UV light ordered from None to Very Strong fluorescence.

Do all diamonds fluorescence?

Roughly 30% of diamonds exhibit fluorescence to some degree.

Does fluorescence affect the value or appearance of a diamond?

It is believed by many professionals in the trade that blue fluorescence in diamonds can help I to M colour grade diamonds appear more coloureless in UV light, such as natural daylight. Because of this benefit, near colourless to faint yellow diamonds with a very strong to medium bluish fluorescence may have a slightly higher per-carat price than similar diamonds that do not have fluorescence in them.

However, diamonds in the D to H colour range with bluish fluorescence are often considered less desirable by the trade for the opposite reason. Meaning, if the bluish fluorescence intensity is very strong in diamonds with these colour grades, they may appear hazy or oily. Still, not all diamonds with very strong bluish fluorescence look oily and on the positive side, they may sell for less than diamonds that do not have blue fluorescence.

Is diamond fluorescence good or bad?

A diamond’s beauty is in the eye of the beholder and therefore some may perceive fluorescence, or some may not. Some may like it, or some may not. Truly, fluorescence does not weaken or has any negative effect on the diamond’s structure and therefore shouldn’t be a major concern when shopping for diamonds.

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