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Identity HelpRed material on copper?
14th Sep 2018 22:50 UTCEmile Osborn
Photo 1: Entire specimen, with a box around general area where photos 2-5 were taken. The deeper red color is more prominent in this photograph than it is when viewing it with the naked eye. Perhaps this can be attributed to the narrower color gamut of a camera sensor+monitor, I don't know.
Photo 2: Stacked image showing the red material (about 3.75X). (There is an X at the same spot on photos 2-5 for general orientation).
Photo 3: Stacked image of the same area as photo 2, under different lighting (i.e., doesn't seem to be an optical effect).
Photos 4-9 continued below.
Thanks for your help!
Emile
14th Sep 2018 22:52 UTCEmile Osborn
Photo 5: View of the region through the camera viewfinder.
Photo 6: Calcite(?) crystals.
14th Sep 2018 22:54 UTCEmile Osborn
Photo 8-9: A few different shots of the copper and matrix.
15th Sep 2018 00:50 UTCScott Rider
My guess is that it could be an alteration of copper into cuprite (https://www.mindat.org/min-1172.html). Sometimes cuprite can be very lustrous and gemmy. I think I see what you are seeing in the 2nd and 3rd images. But I don't see it in the others. Photo 7 is interesting, there is a botryoidal, rounded mineral there. I wouldn't venture a guess to the calcite or epidote. Others will probably ask you to test to verify those, but it looks like the specimen may be too small for that...
I can't tell you if it was cleaned or not, it does look like it was prepared in some way or another. However, I think it could be natural. You never know unless someone analyzed it, which I would not do, in my opinion it looks good the way it is currently. But copper oxidizes in air so the red areas are probably an oxide like cuprite.
15th Sep 2018 00:55 UTCŁukasz Kruszewski Expert
15th Sep 2018 00:55 UTCPaul Brandes 🌟 Manager
I would agree that is a Michigan native copper specimen. The red material “coating” the specimen, to me, looks like a combination of different reflection angles because the copper is so well cleaned, and some odd optical illusions during the photo stacking process. I suppose a way to confirm this would be to use a needle under a microscope and see if any of the red can be scraped off. The white crystals in Photo 6 are indeed calcites that have been severely etched by acid. The gray matrix is basalt. The green crystals are most likely epidote. I also see a little blue on a couple of the shots that could be calumetite.
15th Sep 2018 03:15 UTCEmile Osborn
15th Sep 2018 05:54 UTCDoug Daniels
15th Sep 2018 21:17 UTCEmile Osborn
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Privacy Policy - Terms & Conditions - Contact Us / DMCA issues - Report a bug/vulnerability Current server date and time: May 9, 2024 00:34:01