Autunite (Ca(UO₂)₂(PO₄)₂·10–12H₂O) is a hydrous calcium uranyl phosphate forming brilliant fluorescent yellow-green tabular crystals — among the most strikingly colored uranium minerals. Named after Autun (France), it forms in oxidized cap zones of uranium-bearing pegmatites and granites. Highly radioactive — collector specimens require shielded storage.
Key Facts
- Mohs hardness 2–2.5.
- Tetragonal; thin tabular crystals on basal pinacoid.
- Brilliant lemon-yellow to yellow-green color.
- Strong yellow-green fluorescence under UV.
- Highly radioactive — store in shielded containers.
Notable Localities
Autun (France) is the type-locality. Daybreak Mine (Washington, USA) and Mt. Painter (South Australia) yield collector specimens.
Found at these Localities
- Erzgebirge / Krušné Hory (埃尔茨山脉/克鲁什内山(德捷边境矿带))
- Cornwall Mining District (康沃尔矿区)
