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 Post subject: Curing Opal
PostPosted: Tue Aug 26, 2008 2:44 pm 
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I know that for the most part curing an opal isnt possible. But if there are any methods out there that have given you good results considering the fragility of the opal please let me know. I am trying to get some good tips for my dad who has just started into opals. Its his birthday and he would really love the advice so he can add a few more good opals to his collection from some raw opals He found in nevada. Please any help would be greatly appreciated.


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 Post subject:
PostPosted: Tue Aug 26, 2008 3:37 pm 
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Joined: Mon Jan 15, 2007 6:48 pm
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Location: florida
Hi
:smt006 and welcome

im not sure but other will chime in too with info but i found this place you may ask there


http://www.opalsociety.org/talkshop/messages/292.html


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 Post subject:
PostPosted: Tue Aug 26, 2008 5:27 pm 
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Location: Southern California, U.S.A.
About 30 years ago I spent 2 weeks digging Virgin Valley, NV opals with Keith Hodson, owner of the Rainbow Ridge Mine, one of the oldest and most productive mines in the region. The long and the short of it is that VV opal, along with much beautiful opal found in Idaho, needs a few hundred thousand years' more time to really "stabilize."

It contains too much water. When unearthed the excess water dehydrates rapidly resulting in internal crazing. Keith showed me how you can actually hear freshly-dug VV opal cracking if you hold it to your ear.

His method of finding rare cuttable stones was simple, as he showed me. He placed "likely" rough on the tin roof of his miner's shack during the hot summer weather. Any pieces still solid in the fall he took back to his winter quarters in Scottsdale, AZ, for cutting. Not even all those proved stable. The best chance of finding cuttable opal comes from screening the old tailings piles of clay removed from the underground diggings. For some reason water loss is slowed when the opal remains buried in the tailings for a time and many pieces found that way are cuttable.

A lot of research has gone into attempts to stabilize the material. I keep pretty close track of the field and while I've heard people say for years that a "breakthrough" is coming, I don't yet know of a practical method.

_________________
Rick Martin

www.artcutgems.com


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 Post subject:
PostPosted: Tue Aug 26, 2008 7:23 pm 
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I have to agree with ROM on this. Opal as beautiful as it can be is still a, "Pays your money and takes your chances" gemstone.

By the time it has been mined, fashioned, shipped or set, it's proclivity for crazing may have already been determined.

I've read some experiments on opal, trying to induce crazing by extreme measures with a variety of source material, only to surmise that the tester didn't know why some crazes and some don't.

Given that there are some localities where this is a problem with source material, there are also locations where the material crazing can be indiscriminant.

A wonder of nature and a gamble for investors/buyers.


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 Post subject:
PostPosted: Tue Aug 26, 2008 9:53 pm 
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ROM gives good advice on the curing process. I visited Virgin Valley, Nevada last year and spent several days digging. We ended up finding a lot of nice material mainly due to the fact we were so determined and there was 3 of us. Right now I have a box full of black opal and contraluz in clay sitting in the garage just curing till I get around to cleaning it off. I am hoping for some nice pieces if any.

I also got a lot of conflicting advice from people. Such as putting opal in water and in mineral oil. And even not exposing it to any light and one guy told us there was a process of which to put the opal under pressure and inject it with some kind of oil to keep it stable. I think just leaving it out on your hot tin roof is probably the best idea.

:D


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