General Question

ItalianPrincess1217's avatar

Why would a diamond glow under a black light?

Asked by ItalianPrincess1217 (10534points) April 18th, 2010 from iPhone

My ring has 3 diamonds in the center. One of the side diamonds glow under a black light. What causes this? My fiancĂ© purchased the ring from Kay Jewelers so I’m assuming this doesn’t mean it’s a fake diamond. Right?!

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10 Answers

DarkScribe's avatar

I just checked on some of my wife’s jewelry. They don’t glow – (though they do sparkle as under normal white light). Not under UV light either. Not sure why yours would.

In my younger days while studying I often worked behind bars in clubs that used black light. I did not once see diamond jewelry glow (in the manner that white cotton would for instance) though often it would sparkle enough to catch the eye.

cazzie's avatar

It’s called fluorescence. You can look it up….. It doesn’t mean there’s anything wrong with the stone. It happens naturally. And in some colors, fluorescence can actually enhance a stone’s ability to face up whiter in many lighting situations.

From what I’ve read, it’s a variation in the colour spectrum that diamonds fall under.

here is what I read:

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Captain_Fantasy's avatar

I hear cubic zirconia has that effect. CZ’s display a yellow green color under a shortwave UV source.

Kay is a low end distributor. They take what they can get for as cheap as they can get it. If you have doubts as to the ring’s quality, you should have it appraised.

DarkScribe's avatar

This intrigues me after Googling on it. Apparently twenty percent of diamonds are supposed to fluoresce. We have quite a range of diamond jewelry – all with provenance so known to be genuine. None glow, though with all other light sources off, they do exhibit a faint bluish colour – nothing as bright as a normal “Black Light” glow from something white under IR. More like coral spawn under moonlight. While trying it, my shirt lit up the room, but just a faint glow from the diamonds.

I just tried the UV-C lamp – not as “long wave” as conventional Black Light and that gets a much brighter blue glow. (It is also very dangerous.)

ItalianPrincess1217's avatar

@Captain_Fantasy It doesn’t glow yellow-green. It glows white.
@cazzie Great info! It figures that only one diamond glows. It looks strange and it’s hard to explain to people when they ask. Next time I buy a diamond, I’ll have to bring a black light with me to make sure it doesn’t glow. It’s not a quality I like in my diamonds!

PandoraBoxx's avatar

What are your jewelry purchasing options in your community? If your fiance is in the habit of buying you jewelry, perhaps there are independent options available that deliver better quality for the same cost.

ucme's avatar

Because carats help you see better in the dark?

latanzi's avatar

I know it’s an old thread but I have a genuine diamond that is considered colour G it flouresces magnificantly under blacklight.
To the naked eye the stone appears like any other diamond but the glow is remarkable under the right conditions. Don’t listen to people who suggest your stone is worth much less because it glows, the .27 carat specimen I have was valued at $1900 back in 1993 and at the time was a better quality item than you would find at any chain jewellery store.

Fluthercom23's avatar

I just went to Sterling Hill Mine and Museum in New Jersey. They have a black light room exhibit at the end of the mine tour. The tour guide who was a mechanical engineer, army vet and science guy his whole life, told us among other things that a real diamond with glow under short wave uv light and sure enough, when I held my wedding ring hand under the SHORT wave blacklight, it glowed, my costume cubic z on my right hand did not glow at all. I hope this helps.

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