Boltwoodite
Mineral K(UO2)(SiO3OH)·1.5H2O
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
Pale yellow radiating needles and crusts formed where uraninite alters; superb at the Rössing mine, Namibia, and the Delta mine, Utah. Named for radiochemist Bertram Boltwood.
- Type
- Mineral
- Group
- Silicate (nesosilicate), uranophane group
- Formula
- K(UO2)(SiO3OH)·1.5H2O
- Hardness (Mohs)
- 3.5–4
- Specific gravity
- 4.4–4.7
- Lustre
- pearly, vitreous (glassy), silky
- Crystal system
- Monoclinic
- Colours
- pale yellow
- Transparency
- transparent, translucent
- Cleavage and fracture
- perfect in one direction
- Under UV light
- dull green under shortwave and longwave UV
Typical values: real specimens vary. For more, see mindat.org.