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 Post subject: Octahedron cut with trigons colorless topaz
PostPosted: Thu Jan 07, 2010 1:48 pm 
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Hi, i wanted to know if any of you ever heard about octahedron cut with trigons colorless topaz to be passed as a diamond. I do believe they dont perfectly cut it polish it. Trying to sell it to people who dont carry instruments or dont know much about diamonds.

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PostPosted: Thu Jan 07, 2010 1:54 pm 
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I know the polariscope would instantly separate a topaz from a diamond and with a diamond/moissanite tester u would know it's a diamond(either natural or synthetic)(indentification with portable instrument on the field) do any of you have any idea on separating them if the "diamond" is flawless and quite identical. Thank you.

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PostPosted: Thu Jan 07, 2010 2:33 pm 
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We've featured this on a thread before, which revolved aroundthis story

And here is a link to our thread:
http://gemologyonline.com/Forum/phpBB2/ ... php?t=5222


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PostPosted: Thu Jan 07, 2010 2:56 pm 
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The unsuspecting could also be taken in by flux-grown colorless synthetic spinel octahedra that are both singly refractive and actually have triangular surface markings.

One of the ways to ID them is by the orientation of the markings. In diamonds, trigons don't follow the edges of the crystal, so they don't point to the apex. The reverse is true of the spinel crystals. Of course they wouldn't get past a thermal conductivity tester.

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www.artcutgems.com


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PostPosted: Thu Jan 07, 2010 4:06 pm 
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Thanks a lot Barbra and ROM, very interesting! :smt042


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PostPosted: Thu Jan 07, 2010 8:04 pm 
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do any of you have any idea on separating them if the "diamond" is flawless and quite identical.


Drop it in a glass of water.


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