Do Lab-Grown Diamonds Glow In The Dark?
If you’ve recently purchased or are considering a lab grown diamond, you might wonder about its unique qualities. A question that often comes up is: do lab grown diamonds glow in the dark?
The short answer: no, they don’t. Lab grown diamonds, just like natural-mined diamonds, do not emit light on their own. But under certain conditions — such as exposure to UV light — some diamonds may display a phenomenon known as fluorescence, which is sometimes mistaken for “glowing.”
At Nazar’s & Co. Jewelers, we believe in giving you clear, expert guidance so you can make confident decisions about your fine jewelry. Here’s what you need to know.
Do Diamonds Glow in Complete Darkness?
No. Whether natural or lab grown, diamonds do not glow in total darkness. They don’t have the ability to generate or emit light. What you see sparkling is always the result of light entering the stone, reflecting, and refracting back out.
Diamonds sparkle because of light — not because they glow on their own.
What About Fluorescence?
Some diamonds — both natural and lab grown — exhibit fluorescence. This means they can temporarily glow under ultraviolet (UV) light, such as black lights.
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Colors: The glow is usually blue, but can also appear yellow, green, or even white.
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Strength: Fluorescence varies from faint to very strong.
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Visibility: Once the UV light source is removed, the glow disappears immediately.
Fluorescence is a natural property of some diamonds and does not mean they glow in everyday conditions.
Do Lab Grown Diamonds Fluoresce?
Yes, some lab grown diamonds do. Because they are chemically identical to natural diamonds, they can exhibit the same fluorescence effect under UV light.
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HPHT (High Pressure High Temperature) diamonds often show stronger fluorescence.
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CVD (Chemical Vapor Deposition) diamonds may also fluoresce but tend to show it less intensely.
Key Point: Fluorescence is not a flaw — it’s simply a natural characteristic that can affect how a diamond looks under certain lighting.
Will Fluorescence Affect My Diamond’s Appearance?
In most cases, fluorescence has little to no impact on a diamond’s beauty. For some stones, faint fluorescence can even make the diamond look whiter in daylight. However, very strong fluorescence may give the stone a slightly hazy appearance.
This is why at Nazar’s & Co. Jewelers, we guide our clients through selecting lab grown diamonds that not only meet technical standards but also look their very best in real-world settings.
Why the Confusion About “Glowing”?
It’s easy to see why people think diamonds glow:
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Under bright lights, they appear dazzling and radiant.
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Under black lights, fluorescence can create a temporary glow.
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In dim light, well-cut diamonds capture and reflect even the smallest spark of light.
But remember, this brilliance comes from light interaction, not from the diamond producing light on its own.
Do All Diamonds Have Fluorescence?
Not every diamond shows fluorescence. In fact, most don’t. About 25–30% of diamonds (both natural and lab grown) exhibit some degree of fluorescence under UV light. The majority remain unaffected.
Fluorescence is a natural trait, but not a guarantee.
Does Fluorescence Affect Value?
In most cases, faint to medium fluorescence has little impact on a diamond’s value. Sometimes it can even make a diamond appear whiter in daylight. Very strong fluorescence, however, may reduce value slightly if it causes a hazy appearance.
At Nazar’s & Co. Jewelers, we guide you in choosing stones where fluorescence enhances beauty, not detracts from it.
How to See If Your Diamond Fluoresces
You can check fluorescence easily:
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Shine a black light on the diamond.
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Look for a blue (or sometimes yellow/green) glow.
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Once the light is removed, the glow disappears instantly.
Professional jewelers also include fluorescence grades on official grading reports, so you always know what your diamond exhibits.
Conclusion: Brilliance, Not Glow
So, do lab grown diamonds glow in the dark? No — but like natural diamonds, they can display fluorescence under UV light. This effect can be fascinating, but it’s not the same as glowing in the dark.
At Nazar’s & Co. Jewelers, we’re here to answer all your diamond questions and help you find the perfect piece. Whether you’re looking for a lab grown diamond engagement ring, a designer collection piece, or a custom jewelry creation, our expert team is ready to guide you.
Nazar’s & Co. Jewelers