Do Diamonds Glow Under Black Light?

Do Diamonds Glow Under Black Light?

Diamonds are beautiful and elusive gemstones that attract most people due to their sparkle and brilliance factor. The other interesting property of diamonds that sounds bizarre to most people is that diamonds can produce different glows of different colors under black light.

What Is Diamond Fluorescence?

Natural diamonds have a property known as fluorescence. This phenomenon enables diamonds to produce glows of varied colors when exposed to black light (also known as ultraviolet light). A pure and natural diamond is known to produce a blue glow when exposed to black light. The impure ones have certain chemical impurities that trigger the glow of other colors like green, white, red, and yellow when diamonds are exposed to ultraviolet light. According to the GIA diamond report, more than 65% of diamonds lack fluorescence. Only 30-35 % of diamonds have fluorescence whose glow depends on the strength or intensity of the reaction between their diamond fluorescence and black light.

Is Diamond Fluorescence Bad?

Most people value diamond fluorescence as a form of "defect" in the current diamond markets, which attracts huge sales discounts. However, the misconception seems odd because the product's value is relative and depends on the customers' perspective. People hold this misconception because they believe that diamonds with fluorescence have a hazy or cloudy look that negatively affects the expected beauty and sparkle. The fact is that the brilliance and sparkle of the diamond are determined by its cut quality rather than its ability to glow in UV light. People also think that fluorescence negatively affects the durability of the diamond. This mistaken belief does not always hold because the fluorescence is a characteristic possessed by the chemical impurities in the diamond's composition, which neither interferes with its lattice structure nor weakens its strength or hardness.


Diamond fluorescence is a property found in all diamonds and really is nothing to worry about, but when purchasing a diamond still ask your jeweler about the diamond's fluorescence to see if you are getting the best possible deal. If you need help finding the perfect diamond for your jewelry then get in touch with Mervis Diamond Importers. Our professional jewelers are ready to help you make the right decision when purchasing a diamond or any other piece of jewelry.