That's so chalcopyrite!
this post was submitted on 19 Jul 2026
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Cool Rocks
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A place for:
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Minerals are cool, too.
Be gneiss to each other.
Please use posts for your rocks. Feel free to add more pictures and links to articles in the post text.
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If you are in the Upper Peninsula in Michigan, I HIGHLY recommend visiting the Mineral Museum of the Great Lakes Region (aka the A. E. Seaman Mineral Museum).
They have 4,000 specimens of minerals on display, and 30,000 in the back. And it’s really well done and interesting!
I second this recommendation! The museum alone is worth the trip, but it's also close to copper harbor and lots of rock hounding opportunities. I want to go back for more copper inclusion agates.
Damn that really is a cool rock
So glad I chose Team Rock over Team Stick
Looks like it was hit with a blowtorch. Can this even occur naturally?
It can occur naturally, and I would assume this is a natural one because it was in an excellent museum where they probably would have mentioned if it was altered.
Basically, when it’s found, it’s usually yellow, but as the copper and iron in the mineral react with oxygen and moisture over time, it develops a thin iridescent tarnish.
A very cool rock.