Violet spinel that has red fluorescence.

[T L]

Does anyone have a natural violet or blue spinel with red fluorescence? Please post photos.

 

[stepcutnut]

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

 

[voce]

@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]

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.

 

[T L]

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

Spinel Color and Magnetism, Blue Spinel and Cobalt Spinel

What is spinel? A look at the causes of color and magnetism in natural spinel, synthetic blue spinel and cobalt spinel.

www.gemstonemagnetism.com

 

[voce]

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

Spinel Color and Magnetism, Blue Spinel and Cobalt Spinel

What is spinel? A look at the causes of color and magnetism in natural spinel, synthetic blue spinel and cobalt spinel.

www.gemstonemagnetism.com

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.

 

[stepcutnut]

 

[stepcutnut]

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

 

[T L]

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.

 

[T L]

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]

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]

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]

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!

 

[glitterata]

Definitely sounds interesting!

I'll see if I can get a photo.

 

[Stephan_C]

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]

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]

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.



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.)

 

[stepcutnut]

@glitterata pretty ring! Such great ebay find and the gray spinels are really lovely!

 

[T L]

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.



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.)

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

 

[voce]

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.

 

[Nosean]

The is a Vietnam blue spinel with a strong shift to violet.
LW UV is strong

 

[Nosean]

Vietnam and one Sri Lanka cobalt spinel

 

[YC]

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

 

[T L]

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]

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.

 

[T L]

I wanted to update this thread with this GIA article. I think this explains the fluorescence, and my spinel has the characteristic color and needle inclusions that are in this article. Interesting.

Purple Gem Spinel from Vietnam and Afghanistan: Comparison of Trace Element Chemistry, Cause of Color, and Inclusions

A chemical and spectroscopic comparison of two purple gem spinel samples, one of them the first reported example of a spinel with a saturated purple color caused predominantly by chromium and cobalt.

www.gia.edu

 

[MissyBeaucoup]

@T L Interesting! Thanks for sharing. I love fluorescence!