Uraninite
Mineral UO2
Also called Pitchblende
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.
About it
Very heavy black cubes and octahedrons, or pitch-like botryoidal masses (pitchblende), strongly radioactive and often rimmed with yellow uranium minerals. Notable from Jáchymov, Czechia, and Shinkolobwe, DR Congo.
- Type
- Mineral
- Group
- Oxide, uraninite group
- Formula
- UO2
- Hardness (Mohs)
- 5–6
- Specific gravity
- 6.5–10.9
- Streak
- brownish black
- Lustre
- submetallic, greasy, dull
- Crystal system
- Isometric (cubic)
- Colours
- black, brownish black, grey
- Transparency
- opaque
- Cleavage and fracture
- none; uneven to conchoidal fracture
Typical values: real specimens vary. For more, see mindat.org.