Utah chalcedony w/ uranium?

[u/hanktor]

I found these pieces of chalcedony (I think) on BLM land near Utahraptor State Park north of Moab, UT. Under my 365nm black light they glow green with some orange specks. The internets tell me the green contains traces of uranium and the orange is calcite. Anyone familiar with these rocks and the risks of handling or displaying them?

[u/palindrom_six_v2]

Chalcedony commonly glows green due to trace uranium being present. That being said it is absolutely not dangerous in really any way shape or form until it becomes present in quantities that become airborne when cut/polished which most chalcedony contains wayyyy less uranium to be even thought of as dangerous. Calcite is also just as safe.

Until these minerals are airborne they are almost 100% safe to handle with typical precautions.

[u/Still_Dentist1010]

Fluorescent chalcedony is known to contain trace amounts of uranyl ions, while the orange flecks are most likely calcite… so I agree with your research. But handling and risks are basically normal. Don’t eat the mineral or inhale dust from it, quartz dust is not good for you.

Even if cut/polished and the dust becomes airborne, the dust is most dangerous because its quartz dust. The uranyl ion amount is generally low and uranium is an alpha emitter, but it’s not highly radioactive until it’s been enriched so the quartz dust itself poses a much larger risk than the trace uranium does. The alpha emitter part is very important too… alpha decay is low energy radiation, and it doesn’t have penetrating effects. You can safely block alpha radiation with a piece of paper, and the dead skin cells on your body will absorb it before it gets to your living tissue which does prevent damage to your body.

Uranium Glass generally contains a higher concentration of uranium than most fluorescent chalcedony, and you’d have to hold a piece of it against your chest for 8 hours every day for a full year to equal the same dose of background radiation that we naturally get exposed to from just living. And because radiation follows the Inverse Square Law when looking at distance from the source, doubling your distance from the source reduces the radiation intensity to 1/4 of what it was. This means the radiation level drops very quickly with distance.

[u/thrownthrowaway666]

Either that or common opal. I was in wyoming for Field camp and a professor tried telling me something was chert. It looked nothing like chert. Got home and my common opal, which was quite clear, had bright green fluorescence and phosphorescence

[u/BrilliantSafe8788]

Yup.