Post subject: BE treatment in rough - how to test before you cut
Posted: Sat Jun 13, 2009 3:31 pm
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Joined: Tue May 06, 2008 2:57 pm Posts: 310 Location: Los Angeles
I recently bought a parcel of Umba sapphire. The color ran the gamut from an unusual sea green to almost ruby pink/red. My question - how can you test for BE treatment before a stone is cut? Can you, even? Or test it for BE after it's cut, if you suspect the rough as having been treated?
Second question, does the methyl iodide immersion method for spotting BE treatment work with stones that have been BE treated while they're still rough? These stones are being cut right now, and while I'm not enormously concerned nor would I be angry (well, not too angry LOL) if some tested as BE treated, my main reason for wanting to know isn't just the desire for full disclosure, but also because every time I sell corundum, I'm barraged by questions, and many people want lab reports, or at the very least a gem ID stating what kind of treatment has been done. And I can't blame them, especially if they are putting a lot of $ into a stone. And certainly my pricing would be affected if a stone was BE treated vs heat treatment vs no treatment at all.
Normally I don't send a stone out for a lab report, unless it's a large, good quality stone (over 3 ct, at least); the seller's assurance that the rough is unadulterated has generally been enough for me. Though it wouldn't be unusual to see a parcel of Umba, Tunduru and Songea sapphire mixed together, so I'd like to make sure of because I fear unintentionally misrepresenting an item.
I've also been told that Umba sapphires are resistant to any type of treatment. Anyone else heard this?
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