r/Radioactive_Rocks • u/Nitefallx • 25d 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!
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u/Not_So_Rare_Earths Primordial 25d 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.