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Post by orrum on Mar 21, 2023 10:46:23 GMT -5
I heard the pit is so undercut that it's dangerous to dig. The overburden would cost a fortune to remove.
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realrockhound
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Chucking leaverite at tweekers
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Post by realrockhound on Mar 21, 2023 10:58:06 GMT -5
I heard the pit is so undercut that it's dangerous to dig. The overburden would cost a fortune to remove. Very well could be. I’ve seen golf ball sized pieces going for $40+ online
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Fossilman
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Post by Fossilman on Mar 26, 2023 10:26:13 GMT -5
A lot of green slag glass gets passed off as obsidian, gotta watch that for sure.. As for transparent obsidian, I have seen some at Glass Buttes ( private claim), it's totally beautiful material.."Very very very smooth" As for green obsidian, I have seen it from the Hines/Burns, Oregon area. I have a small piece of green obsidian rough in my collection, probably just leave it as it is .. It's out there, just do your homework when buying it..
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docharber
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Post by docharber on Apr 17, 2023 23:39:12 GMT -5
OK. Obsidian is just volcanic glass from lava very high in silica. It CAN have high transparency. It ain't obsidian since it came from Indiana unless someone buried part of their collection there. This is SLAG which can contain any combination of colors. Light bottle-glass green obsidian is found in Ethiopia. I like the exploding comet idea but fused sand would not be transparent, as Ethiopian obsidian is. A small amount of emerald-green obsidian, as I understand the history of Helenite, was found on Mt. St. Helens and prompted somewhat shady marketers (Stauer and others) to market a man-made glass containing and colored by volcanic ash from the eruption and other additives as Helenite. Thousands have purchased this attractive glass thinking it is natural, and the ads in respectable publications like Smithsonian carefully avoid saying it's natural. Again, a natural emerald green obsidian is also found in Africa (not sure exactly where) and my wife has gotgrous emerald-cut stud earrings made of it. I bought them, set in gold, from a a friend and dealer I know to be extremely knowledgeable and honest. As for hardness, glass can be fairly hard or soft depending on its composition and tempering. To sum it up, the pics are slag, but similar light green obsidian exists. Helenite is man-made but similarly colored obsidian also exists. On the discussion about arsenic and lead, I think you're safe cutting them wet but care should be taken about disposal of slurry. Arsenic is a bleaching agent that reacts with iron (cause of bottle glass green color) to render the glass colorless. Waterford became famous because their sand was largely iron free. The arsenic bleaching technigue dates to very ancient glassmaking in the middle east. in the 19th century manganese compounds were used for bleaching. With UV exposure the manganese will be reduced (chemically speaking) to a colloidal state creating a violet tint many of you may have noticed at some point. The color we usually associate with obsidian, from black/grey to browns and green colors, is due to iron and magnesium compounds (ferromagnesian minerals). Think of olivine and other blackish iron/ magnesium minerals found in most lavas and pegmatites in abundance.
UPDATE: I researched further and....never mind. According to Geology.com Helenite originated when workers using an acetylene torch in salvage work post the 1980 Mt. St. Helens eruption accidentally created a green glass by melting ash. the marketing folks took it from there and mass quantities of man-made glass dubbed Helenite was produced and sold as if it were of value. It isn't. It contains a token amount of ash but it is basically artificially colored glass. I didn't know until today that it was also made in red and blue. now I'm thinking there may be no natural emerald green obsidian and my wife's earrings, though in gold, are just cheap green glass. they are pretty, though. I do maintain there is light bottle-glass green obsidian from Ethiopia as I have seen it. There is also dark olive green, opaque to translucent obsidian which isn't terribly uncommon. So, I stand corrected. Excuse me while I go flog myself in penance.
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