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 Post subject: Russian Demantoid - Heat treatment
PostPosted: Sun Jan 03, 2016 10:22 am 
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Very interesting!

http://www.igc-gemmology.net/igc34-proc ... GC3444.pdf

[pdfview]http://www.igc-gemmology.net/igc34-proceedings/content/pdf/IGC3444.pdf[/pdfview]

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 Post subject: Re: Russian Demantoid - Heat treatment
PostPosted: Sun Jan 03, 2016 3:21 pm 
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That is fascinating, and somewhat contrary to what I'd heard elsewhere--I know it's said that heat treatment on demantoids is a very low temperature process. I'd even heared numbers like 100c thrown around if I remember right. That aside, it is a rare treat to see such a nicely documented article on a treatment like this.

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 Post subject: Re: Russian Demantoid - Heat treatment
PostPosted: Sun Jan 03, 2016 4:08 pm 
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Interesting and a question to our mayor labs - maybe Mr. Renfro or Mr. Smith can help - whether FTIR now helps to identify heat treated russian** demantoid with horsetail inclusion so many buyer and collector wanna see?

**

To my knowledge skarn hosted demantoid like Madagascar or Namibia show no fibers of asbest minerals. The serpentinite hosted D. show fibers ( Val Malenco, Iran, Pakistan)
but not the horsetails like the russian stones ( don't know much about Canada and Californian D.)

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