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.
Joined: Fri Feb 24, 2006 1:20 am Posts: 2649 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.
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.
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