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 Post subject: Color Change Pyralspite heavy on Spessartine
PostPosted: Wed Jan 20, 2021 1:33 pm 
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I was brought a color change garnet for identification yesterday and it tested as spessartine on the gemmoraman.
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The owner said, "It's a color change garnet. It CAN'T be spessartine."
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I did some research and there appears to be a notation in the literature.
https://www.typeiiadiamond.com/2019/08/ ... st-report/

Can anyone add information about color change spessartine?


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 Post subject: Re: Color Change Pyralspite heavy on Spessartine
PostPosted: Wed Jan 20, 2021 2:09 pm 
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Well all of these garnets are in the pyralspite mixture family. I see no reason that a color change stone couldn't have a mixture that is heavily weighted to the spessartine end member side.

What RI did you get on the stone? I suspect it would be on the lower end of the spessartine range +- 1.77, 1.78 area.

If so, even if Raman says Spessartine I would be tempted to use the pyrope - almandine - spessartine designation in the formal ID. The mix requirements to name something as an end member is fuzzy and depends on who you ask. Calling it a mix and you for sure won't be wrong.

The RAMAN database shows a match to a stone that was entered as a spessartine. But was that sample actually a pure end member stone?

By the way, that is a great looking garnet!


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 Post subject: Re: Color Change Pyralspite heavy on Spessartine
PostPosted: Wed Jan 20, 2021 2:40 pm 
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Would you mind emailing me the spectrum?

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 Post subject: Re: Color Change Pyralspite heavy on Spessartine
PostPosted: Wed Jan 20, 2021 2:48 pm 
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Coming up.
I still have the ring and the spectrum I posted above is the 2nd match on the results. The first was spessartine: red.
I'll also take an RI


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 Post subject: Re: Color Change Pyralspite
PostPosted: Wed Jan 20, 2021 5:41 pm 
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RI: 1.777 (RI liquid :1.81; Eickhorst Refractometer)

Inclusion scene: Intersecting rutile needles and transparent blue/green xls, I suspect apatite.

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 Post subject: Re: Color Change Pyralspite heavy on Spessartine
PostPosted: Thu Jan 21, 2021 2:12 pm 
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The low RI kind of confirms my instincts on the PYRALSPITE call.


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 Post subject: Re: Color Change Pyralspite heavy on Spessartine
PostPosted: Thu Jan 21, 2021 2:32 pm 
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Agreed.


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 Post subject: Re: Color Change Pyralspite heavy on Spessartine
PostPosted: Fri Jan 22, 2021 8:09 pm 
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My calculations put this at (approximately) about 63% spessartine, 34% pyrope and 3% almandine

So... little almandine


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 Post subject: Re: Color Change Pyralspite heavy on Spessartine
PostPosted: Fri Jan 22, 2021 8:31 pm 
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dchallener wrote:
My calculations put this at (approximately) about 63% spessartine, 34% pyrope and 3% almandine

So... little almandine



Since most color change garnet is primarily a spessartine - pyrope mix, everything is consistent.


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 Post subject: Re: Color Change Pyralspite heavy on Spessartine
PostPosted: Mon Jan 25, 2021 5:32 pm 
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I am really into Color Change Gemstones!

This one is definitely a Pyrope-Spessartite Garnet. Their range between the two groups changes substantially amongst all color change stones. Check the graph here:
https://www.gemstonemagnetism.com/color ... arnet.html


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 Post subject: Re: Color Change Pyralspite heavy on Spessartine
PostPosted: Mon Jan 25, 2021 7:08 pm 
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I don't want to split hairs, but I think the Spessartine % would make it a Spessartine Pyrope. :wink:


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 Post subject: Re: Color Change Pyralspite heavy on Spessartine
PostPosted: Tue Jan 26, 2021 11:08 pm 
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Barbra! :P

what about if we take the color system from GIA and have fun ! it could be named: slightly pyropish Spessartite or slpS
:)


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 Post subject: Re: Color Change Pyralspite heavy on Spessartine
PostPosted: Tue Jan 26, 2021 11:11 pm 
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There you go. Brilliant. I think you should propose the new classification. :wink:


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