Kaersutite
Mineral NaCa2(Mg3TiAl)(Si6Al2)O22O2
About it
Glossy black to dark brown titanium amphibole, often as large loose crystals in alkali basalt and tuff; named for Qaersut, Greenland, with fine crystals from Vlčí Hora, Czech Republic.
- Type
- Mineral
- Group
- Silicate (inosilicate), amphibole group
- Formula
- NaCa2(Mg3TiAl)(Si6Al2)O22O2
- Hardness (Mohs)
- 5–6
- Specific gravity
- 3.2–3.28
- Streak
- light brown
- Lustre
- vitreous (glassy)
- Crystal system
- Monoclinic
- Colours
- dark brown, black
- Transparency
- transparent, translucent, opaque
- Cleavage and fracture
- perfect in two directions at about 56° and 124°
Typical values: real specimens vary. For more, see mindat.org.