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Violet spinel that has red fluorescence.

stepcutnut

Ideal_Rock
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Aug 11, 2008
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Hi @T L I do have a round grape jelly colored spinel with red fluorescence, I will try and take some pics as soon as this storm lets up. I find fluorescence really fascinating :)
 
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voce

Ideal_Rock
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@T L @stepcutnut
I do not have a bluish or purple natural spinel with red fluorescence like that. A vendor has told me before, that any blue or purple spinel with UV fluorescence is synthetic.

https://ui.adsabs.harvard.edu/abs/2019PCM....46..343A/abstract

My own internet based research suggests the same conclusion. Given that blue and purple colors in sapphire and spinel require fluorescence-quenching iron (Fe) to be present.

None of my real or blue or purple spinels I've bought from various trusted vendors, from Burma or Africa, have ever fluoresced. My lavender sapphires weakly fluoresce, and the darker purple sapphires don't fluoresce, probably because there's more iron with more saturated color. So I think the strong fluorescence indicates your stone is probably synthetic.
 

T L

Super_Ideal_Rock
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It could be synthetic, but there is a slight grey undertone. The synthetics that were around 15 years ago seemed colors that were too good to be true for spinel, like neon or pale blue. The color is very similar to some of the blue spinels I own that have natural inclusions. I’m wondering if it’s a sapphire instead (whether natural or synthetic). The fourth photo shows the grayish undertone in diffused natural light.

I do know some blue sapphires fluoresce red. I have to find my loupe!! I need to see if there are inclusions.
 
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voce

Ideal_Rock
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I found this online. My spinel is very similar to the one on the left in color.


7D2974D9-2D78-48BC-8A13-90E4E8E84820.jpeg

Good information at that link. Cobalt can also be a blue color chromophore, and they're saying that spinels with a high cobalt content will fluoresce because there's less iron to quench the fluorescence. Just given the rarity of cobalt spinels, I would want a lab report before claiming my spinel had cobalt.
 
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stepcutnut

Ideal_Rock
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It was purchased from Barry Bridgestock in 2008 as Burmese. Tough to capture the fluorescence with my phone.
 

T L

Super_Ideal_Rock
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Good information at that link. Cobalt can also be a blue color chromophore, and they're saying that spinels with a high cobalt content will fluoresce because there's less iron to quench the fluorescence. Just given the rarity of cobalt spinels, I would want a lab report before claiming my spinel had cobalt.
Absolutely!
 

glitterata

Ideal_Rock
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I have a gray spinel that looks a little bluish/purplish in some lighting and fluoresces faintly pink, if that is at all interesting. Which it probably isn't.
 

stepcutnut

Ideal_Rock
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That’s so pretty!! It definitely has a reddish component to the color, indicating there may be chromium, hence why it may fluoresce. Thanks for the photos.

Thanks @T L I really love this stone but sadly don’t wear the ring often. All because one of the prongs on the tulip setting is a bit wonky after coming back from the setter and it has always bothered me. After wearing it around today I think I need to have it reset so I can enjoy wearing it again :)
 

T L

Super_Ideal_Rock
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I have a gray spinel that looks a little bluish/purplish in some lighting and fluoresces faintly pink, if that is at all interesting. Which it probably isn't.

Definitely sounds interesting!
 

Stephan_C

Rough_Rock
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Purple/violet spinels with red/pink fluorescence are frequently seen, natural stones, of course.
Some orange, blue, grey, mauve spinels also fluorescent.
Once there was a color changing spinel, blue to violet, with red fluorescence under uv light, very interesting piece, one stone, three shades in various lighting conditions, sounds like ‘buy one get two free’, lol
 

T L

Super_Ideal_Rock
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Purple/violet spinels with red/pink fluorescence are frequently seen, natural stones, of course.
Some orange, blue, grey, mauve spinels also fluorescent.
Once there was a color changing spinel, blue to violet, with red fluorescence under uv light, very interesting piece, one stone, three shades in various lighting conditions, sounds like ‘buy one get two free’, lol

Interesting, there’s so little on the internet about natural violet/blue/purple spinels with red fluorescence, which is why I opened this thread. Only fluorescence is discussed in red family and synthetic spinel.
 

glitterata

Ideal_Rock
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Definitely sounds interesting!

I couldn't get the blacklight photos to come out as anything but a purple blur, but here's a photo under cool LED light of my ring set with two gray spinels. The lighter one, which looks more gray and less bluish than the darker one in this photo, definitely fluoresces pink, even though I can't get a good picture of the fluorescence. By the way, the blue background is the blue cover of a book--it's not color distortion.

IMG_4161.jpg

Here are a couple of very old photos of this ring in different lighting, from when my hands were much younger. (This was an old setting I bought cheap in the glory days of eBay and set with a pair of gray spinels--back then nobody wanted gray spinels, and you could buy them for the price of a nice lunch.)

grayspinelsgl6.jpg grayspinelsgl7.jpg grayspinelsgl8.jpg
 

T L

Super_Ideal_Rock
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I couldn't get the blacklight photos to come out as anything but a purple blur, but here's a photo under cool LED light of my ring set with two gray spinels. The lighter one, which looks more gray and less bluish than the darker one in this photo, definitely fluoresces pink, even though I can't get a good picture of the fluorescence. By the way, the blue background is the blue cover of a book--it's not color distortion.

IMG_4161.jpg

Here are a couple of very old photos of this ring in different lighting, from when my hands were much younger. (This was an old setting I bought cheap in the glory days of eBay and set with a pair of gray spinels--back then nobody wanted gray spinels, and you could buy them for the price of a nice lunch.)

grayspinelsgl6.jpg grayspinelsgl7.jpg grayspinelsgl8.jpg

Those are lovely spinels and such a nice vintage setting. Thank you for sharing!
 

voce

Ideal_Rock
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Lovely spinel, stepcutnut!

That looks like what I would call weak florescence, similar to what you would find in lavender and purple sapphires. It's not strong like T L's, which is similar to lab spinel and cobalt spinel.

I hope you find more opportunities to wear the spinel, as I find that to be a lovely shade of purple.
 

YC

Brilliant_Rock
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20210606_154156.jpg 20210606_153915.jpg

Interesting thread. My lavender Myanmar spinel shows strong fluorescence and I have often wondered why.
 

T L

Super_Ideal_Rock
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I’m suspecting the presence of chromium is causing the fluorescence. In what would have been a more blue spinel, blue + red = purple, so since chromium adds the reddish/pink component, many of these fluorescent spinels have a violet, purple or lavender color.

Cobalt supposedly can cause fluorescence too, which is the case for the more vivid blue colors.
 

T L

Super_Ideal_Rock
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I obtained a loupe with a bright led light, and my above referenced spinel has obvious needle and crystal inclusions that are significant, but not seen with the unaided eye, so I believe it’s natural.
 
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