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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!
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.