CIBJO releases Gemmological Special Report: considers process of separating measurable facts from opinion; See Gemological Articles below.
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 Post subject: Need some help with treated flame fusion synthetic corrundum
PostPosted: Mon Sep 03, 2012 7:24 pm 
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Okay,

Some questions for you experts (I am new to these forums, but have been around awhile).

I have now seen heat treated flame fusion corrundum where the stria lines have been sucesfully removed. Now without the lines, there are the characteristic bubbles right? BUT The bubbles are not uniform throughout the boule...in a cut stone with no stria and no bubbles..what other options for identification do I have?

Other questions......why couldn't the treaters simply REMELT the boule in say an induction furnace and agitate the melt (to remove bubbles) and let the mass congeal? (I generaly know nothing about this topic, I am just pondering)

Aheim, if I have a suspected "treated" bubble less flame fusion corrundum, will the GIA's (I think is it 118$ now) service be able to tell me with certainty the oragin?

Thanks all

v/r

John


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 Post subject: Re: Need some help with treated flame fusion synthetic corru
PostPosted: Tue Sep 04, 2012 8:45 am 
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Re: melting the boule. The challenge in synthesis is making a single large continuous crystal, which would then have all the desired properties of the mineral in question. If they melted it that would disrupt the crystal lattice and you would be back to square one--if you just melt it and let it solidify it would be corundum glass, not corundum.


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 Post subject: Re: Need some help with treated flame fusion synthetic corru
PostPosted: Tue Sep 04, 2012 11:13 am 
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Quote:
I have now seen heat treated flame fusion corrundum where the stria lines have been sucesfully removed.


Can you supply references to this? I'm not familiar with this process.

It is my understanding that even Czochralski grown Ruby used for laser applications may have minute bubbles visible with microscopic observation.

Quote:
Aheim, if I have a suspected "treated" bubble less flame fusion corrundum, will the GIA's (I think is it 118$ now) service be able to tell me with certainty the oragin?

Yes, any well equipped lab can distinguish a natural from flame fusion ruby, with or without bubbles or striae. It would be determined by the presence (or lack of) trace elements.


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