Samarskite-(Y)
Mineral (Y,Fe,U)(Nb,Ta)O4
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
Velvety-black, pitchy crystals in granite pegmatites, radioactive and usually glassy inside from radiation damage. The element samarium was found in it and named after it; known from the Urals and North Carolina's Spruce Pine district.
- Type
- Mineral
- Group
- Oxide, samarskite group
- Formula
- (Y,Fe,U)(Nb,Ta)O4
- Hardness (Mohs)
- 5–6
- Specific gravity
- 5–5.8
- Streak
- dark reddish brown
- Lustre
- vitreous (glassy), resinous, submetallic
- Crystal system
- Monoclinic
- Colours
- black, brownish black
- Transparency
- opaque
- Cleavage and fracture
- indistinct; conchoidal fracture
Typical values: real specimens vary. For more, see mindat.org.