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After more research and some lucky talks I believe this to be epidote from tailings out of the Wolverine Mine, a few miles from where I found these pieces.
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Was rock hounding on the southern shore of Lake Superior. Found these green crystal deposits that formed like geodes, specimens are small, the largest is about the size of a corn kernel. A local said it could be chlorasolite but I don’t think it matches based on color and clarity. Any thoughts would be appreciated!
People generally think rocks are pretty harmless, but they really shouldn’t.
Once you know the basics of geology or mineralogy you can look up the metal composition of most of the rocks you find in your environment. After that, there’s no turning back. You’ll never want to lick another random rock again, and you’ll be more cautions about breathing in rock dust.
This is horrifying and not surprising. I found these pieces on a beach, but noticed they were ubiquitous in almost all the crushed gravel I saw in the town (driveways, fill under roads etc). They seem to have been using copper tailings for all sorts of construction for a long time. I hope it isn’t some nasty concoction, if it is those towns are a fema project waiting to happen.
Better send some samples to your local friendly mineralogist. Usually the geological survey of your home country should be able to help. There’s also a good chance these rocks contain boring silicon oxide hydroxide whatever with a little it of calcium and sodium thrown in for color. It’s too early to tell without having them properly analyzed.