Lapidaryforum.net
Let's Rock => Opal => Topic started by: John Robinson on October 06, 2017, 08:31:04 AM
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I have a nice little opal with one glaring flaw, a crack that was barely visible until it got some cerium oxide in it while polishing, can it be fixed or do I have to trash the stone?
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You'll have to get the cerium oxide out before deciding whether to do anything else. If you have an old "Waterpic" or similar pulsing tooth cleaning spray (or can pick one up cheap at a thrift store), that can often get out polish from cracks (use warm water with a bit of hand dishwashing detergent in the reservoir).
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That's what I use, a waterpick, and I thought I was the only one! Everyone I know seems to have an ultrasonic.
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I have also used a simple hose with a sprayer throttled down to a forceful mist, up against the stone this has a lot of power to remove the debris if you don't have a waterpic. I have used Hxtal on opal as a fracture sealer with good results.
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Ultrasonics and opal are a big no-no. :nono:
Don't want the opal to explode!
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But you get a bunch of clean stones instead of just one. Win win right?
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Depends. If there were cracks already, probably. If there are no cracks in it, because of the small water content in opal, the ultrasonic would vibrate that water as well the water it was in and it could literally explode when it was a perfectly fine stone before it went it. No so sure that's a win-win.
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Thanks all!
I just cut the opal at the crack. I could have sworn it was not an open crack when I started polishing, but the heat could have had something to do with it opening up?
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Totally possible. A crack is a weak spot in the stone. Heat, the vibration from your wheel, the stars aligning the wrong way ....