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 Post subject: Red fluorescence on a blue gem.
PostPosted: Tue Mar 08, 2011 2:40 pm 
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Hello,

So I recently bought a watch to sell it again. It has diamonds, my Moissanite/Diamond tester did all the job.
And then I came across with a small blue stone. My color gem tester says it's topaz but I know that testers are not always enough.
I used my UV light and then this little gem showed up red!
Can anyone please help me identifying this little blue gem? :(


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 Post subject: Re: Red fluorescence on a blue gem.
PostPosted: Tue Mar 08, 2011 3:33 pm 
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Location: San Francisco
There are free beginning courses to read on the left.
This is not a consumer's board.

For us to help here, we would minimally need to know if the gem is singly or doubly refractive, polariscope reaction, refractive index, microscopic observations. UV can be helpful. I presume you have only LWUV.

Can you supply any more information?

I would be curious about SWUV reaction coupled with polariscope reaction.


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 Post subject: Re: Red fluorescence on a blue gem.
PostPosted: Sat May 07, 2011 2:27 pm 
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Dear Estellise, I observe that blue synthetic spinel color by cobalt mostly show red in UV (SW).

HUK

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 Post subject: Re: Red fluorescence on a blue gem.
PostPosted: Thu May 12, 2011 12:07 pm 
Red fluorescence is normally associated with chromium or cobalt. Of those two, cobalt is the one associated with a blue body colour, so Osman is probably right.

SR in a polariscope (x-hatch AE effect?) + "thick-thick-thin syn-spin"* lines through a spectroscope would be diagnostic.

* Nearly all cobalt blue spinels are synthetic, but th very few natural Co-spinels would also obviously show this absorption pattern.


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