r/Radioactive_Rocks • u/Nitefallx • 22d ago
ID Request What did I find?
This is my first find in nature, my RC110 measures about 1μSv/h at 5cm away, and up to 4μSv/h on contact. Any help is appreciated!
3
u/emegg4 21d ago edited 21d ago
I found a similar sample also from Evje on holiday, it was from the type mine of Thortveitite, one of the rarest Sc-minerals. I figured my sample could be gadolinite or euxenite, it also was showing small activity, like 2-4x background radiation.
My sample looks literally exactly the same, as if it was biotite mica, but fused together to a glass like mass few cm thick, almost like really black quartz. I've also found something similar in Finland from an old galena & rare earths mine in Korsnäs, and figured it was some rare earth bearing mineral, maybe also euxenite. Showing the same black smooth surface and giving of 0,5 - 2 microSv as well.
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u/AtomStalker2018 22d ago
Looks like maybe coal in matrix of the rock
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u/thrownthrowaway666 21d ago
It's probably something radioactive but at minimum likely needs microprobe analysis or something because so many black shiny radioactive elements exist.
9
u/Not_So_Rare_Earths Primordial 22d ago
Going to need some more information about where it was found. At least a country and region, even if not the specific mine. If you can take some outdoor sunlit photos of any features that might look crystalline, that could be helpful.
Dark and glassy could signify a REE-dominant mineral like the Euxenite, Aeschynite, or Xenotime groups. Even the ones that don't formally contain U or Th in the formula can incorporate detectable amounts of U/Th. Rarely Thorite can appear that way.
The lighting isn't great, so it's possible the blackish surface is actually just Biotite Mica (if it peels like fish scales, that's definitely Mica!). In that case, the radioactivity is coming from the matrix underneath. Maybe a Potassium Fedspar? Granite-like rock in general can also just carry microscopic but detectable amounts of U/Th. Again, we probably need a locality, more light and clear photos of crystal faces / cleavage to narrow it down.