gemfeller
Cave Dweller 
Member since June 2011
Posts: 4,060 
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Post by gemfeller on Dec 7, 2022 22:22:12 GMT -5
Nice. It should be a dandy when it's dried out. Hydrophane opal like Welo is always a crapshoot. Most loses the water absorbed during cutting and resumes its original clarity and color. Sadly, some will crack after cutting. Time to get back to its original appearance varies a lot, from hours to a couple of weeks.
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Post by rockjunquie on Dec 8, 2022 6:04:05 GMT -5
Another opal; another home run.  |
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Post by jasoninsd on Dec 8, 2022 6:57:36 GMT -5
Another opal; another home run. That's funny*...that's what I was going to say! *Funny as in "odd"...not funny as in "ha ha"!  Bravura Cabochon Designs - These are really fascinating...especially reading about the "drying out" period. If you remember...and are so inclined...I'd love to see some pictures of what they look like once they've dried out. |
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Post by hummingbirdstones on Dec 8, 2022 10:06:15 GMT -5
Nice. It should be a dandy when it's dried out. Hydrophane opal like Welo is always a crapshoot. Most loses the water absorbed during cutting and resumes its original clarity and color. Sadly, some will crack after cutting. Time to get back to its original appearance varies a lot, from hours to a couple of weeks. Thanks. My friend who gave me the rough said not to worry, but the effect of the water really freaks me out lol! I don't mean to pee in your Corn Flakes this morning, but the only Welo I ever cut never turned back clear. I have never cut another one.  I hope yours comes back. It looks like it will be killer if it does! . |
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Post by jasoninsd on Dec 8, 2022 13:35:54 GMT -5
hummingbirdstones that must have been a little disappointing, but also a valuable lesson. jasoninsd the one I cut the day before yesterday is already clearing up, here’s a side by side comparison.  Thanks for doing the "side by side" pic! I've only worked one material where water affected it...and that was Batcave Jasper. The cab would become saturated with water, and would need to actually dry out after working it. In fact, it worked better on the 2000+ wheels working it dry rather than wet. Not real good for the diamond wheels though! LOL |
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gemfeller
Cave Dweller
Member since June 2011
Posts: 4,060
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Post by gemfeller on Dec 8, 2022 15:45:55 GMT -5
Hydrophane opal is strange. My first experience with it was when cutting a piece of orange Mexican opal (fire opal) I thought had no play of color. But when it became saturated with water it showed brilliant color-play, just the opposite of Welo. It lost the color when it dried out.
Opal is a mineraloid, not a specific mineral. In its different phases it displays unusual properties like hydrophane and contra-luz (against the light) which shows play of color only with transmitted light. I have searched (maybe not hard enough) for a scientific explanation but haven't found one.
All opal (except synthetic) contains water in various proportions. The amount of water seems to determine whether the opal remains stable or will craze when it dehydrates a bit.
I once spent a week mining in Virgin Valley, NV with the owner of a famous opal mine there. The mine's opal is contained in a wet, dense clay mostly as a wood replacement including pine cones. The miner found a little pocket of opal and we walked out into the sunshine. He held it to my ear and after a few moments I could actually hear popping sounds as it quickly dried and crazed. Yet when such opal sits in the spoils outdoors for a year or two it can lose water slowly enough to finally reach equilibrium and is often stable and cuttable.
I'm an opal nut. In my mind no other natural stone combines such incredible beauty with so much innate scientific mystery. Once you catch the opal bug you'll be infected for life.
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