Autunite
Mineral Ca(UO2)2(PO4)2·10-12H2O
Take care.
- Radioactive: Keep it in a closed, labelled box away from where people sit or sleep, handle it briefly, wash your hands after, and never grind or cut it.
- Fragile: Handle it gently and pack it well; it breaks or crumbles easily.
About it
Square yellow-green flakes that glow intensely under UV; radioactive from uranium. Slowly loses water to meta-autunite in dry air. Famous from the Daybreak mine near Mount Spokane, Washington, and Autun in France.
- Type
- Mineral
- Group
- Phosphate, autunite group (uranyl)
- Formula
- Ca(UO2)2(PO4)2·10-12H2O
- Hardness (Mohs)
- 2–2.5
- Specific gravity
- 3.1–3.2
- Streak
- pale yellow
- Lustre
- vitreous (glassy), pearly
- Crystal system
- Tetragonal
- Colours
- lemon yellow, sulfur yellow, greenish yellow, pale green
- Transparency
- transparent, translucent
- Cleavage and fracture
- perfect in one direction, mica-like flakes
- Under UV light
- bright yellow-green under longwave and shortwave UV
Typical values: real specimens vary. For more, see mindat.org.