January 24 Through February 4—TUCSON, ARIZONA: Annual show
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 Post subject: Two sapphires
PostPosted: Sat Mar 10, 2018 8:25 pm 
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So, in my continued exploration of microscopy I took a look inside two sapphires I bought last year at the Franklin gem shows. Both were very cheap, sold as part of a mixed lot with a variety of neat stones. No details or disclosures were provided with them--I suspect they were originally JTV purchases that someone picked up in an estate since a few of the gem jars had half-removed familiar-looking barcodes. I did use our raman to confirm they are both corundum. I am not sure what to look for to check for heat, but both do have fine intact rutile needles that seem promising.
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The first stone is a nice light yellow 1 carat oval. It shows a pronounced golden sheen when viewed from the side. Click inclusion pictures for larger versions.
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As you would guess the sheen seems to be provided by flat hematite/ilmenite crystals. They're irridescent through the scope but that is hard to pick up on camera. There are a few thin needles mixed in which I assume are minor exsolved rutile--they appear to be intact, which I'd guess is a good sign with regards to heat?
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The second one is a 1.18ct milky blue-violet pear.
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This one is shot through with these fine crystal(?) inclusions, with minor rutile needles in between. Again, the rutile appears to be intact. I did look at the stone under crossed polars using my gemoaid microscope kit, and they do show up bright against the dark corundum background which I assume indicates they're crystal inclusions that are repolarizing the light and not negative crystals?
Anyway, there is a lot to learn!

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 Post subject: Re: Two sapphires
PostPosted: Sat Mar 10, 2018 11:09 pm 
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Stephen, do you have an immersion style microscope you could view these saphs with?
A little methylene iodide could be insightful.


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 Post subject: Re: Two sapphires
PostPosted: Fri Mar 16, 2018 9:22 am 
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To me both are unheated

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