Diamond fluorescence? What is this pink glow?

hello, I purchased a GIA L Si2 earth grown diamond with very strong blue fluorescence. I am enjoying it as a specimen/collection stone. It is also white phosphorescent.

My question is why would it have a strange purple hue in UV? I could understand a blue, or an oily look, but I have seen and photographed a color that doesnt match blue. Any idea what could cause this?

Posting pics to show the pinkish purple hue in UV. Thanks in advance for any ideas!

No UV, indoor

Outdoor (you can see the pinkish hue next to non floro diamonds)

Under 395 UV

In the car, with some UV from the side window. I am not wearing pink or have any pink in the environment.

Is this an overblue? What the heck is the pink?

It is difficult to grade diamonds color-wise, while set in jewelry. The reason being how reflected light off of surrounding surfaces can influence the perceived color. The last image does show a slight pink hue.

As for the fluorescence, diamond is known to have a variety of visible reactions to UV: Diamond gemstone information This is a fairly thorough resource on gemstones that describes the fluorescence behavior. Your UV light; is it a single wavelength band? (I.e. Short, Medium, or Long Wave)

The pink undertone may have been the reason it was given an “L” in color grade. https://4cs.gia.edu/en-us/blog/gia-diamond-grading-scales/

It is indeed a nice looking stone! Lastly, were you given a copy of the GIA certificate/Report?

Hi Troy,
I appreciate you taking the time to look at this stone. Loupe360
GIA 6431416590. Something about the video I liked (I think the way the colors dispersed). Indoors, the color is and was a typical L warm stone. No pink. When I go outside, in the shade it is a typical fluorescent blue, but in the sun rays, the stone gets pinkish over a few minutes.

Today is overcast and going outside, the stone did seem to improve a shade or two, but did not have any pinkness or glow effect, even after a few minutes.

Could it be possible the pink in bright light is due to your skin? A reflection off your skin? Just a thought. I’m very very ignorant when it comes to diamonds.

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Bob, I am open to any guesses! Probably not skin or clothes or environment. My other diamonds do not change at all in the same light as “control samples”. Just this one.

Hi Laura,

The GIA report is valid! (Always have to check… sorry old habit). The report does identify the strong UV reaction and annotates the report serial inscription on the stone girdle! Always good for traceability… :slight_smile: … The inclusion map is always fun to explore, especially after seeing the video at Loupe360.

Photo-chromism is something that might explain the pink tint… here is an article that is based on published works… I don’t have access to the original data or I would dive into it further.

I learn something new everyday…


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Thanks again Troy,
The report was verified when I received the diamond. While not conventionally beautiful, the round crystals inside were pretty interesting (I have diamonds in my diamonds :). This stone was not that pricy and I actually thought it was an interesting specimen rock I would wear. I did not bargain on the whole pink effect. I expected bluish hazy effect.

Digging around, I found this article: Are There Color Change Diamonds? - International Gem Society
but then found a mention of a diamond that has a color change effect and turned light pink in fluorescence/daylight. Then that lead to this article https://accreditedgemologists.org/lightingtaskforce/2010/tavernier.pdf

Not trying to over think this, but sure it is light wavelength activated. Would be cool if this was the alexandrite effect.

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Your diamond seems to check some if not most of those key behaviors to be classified for the alexandrite effect. And it obviously, does become radiant with the pink undertone in the sunlight… not much more evidence is needed, honestly.


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