Hibonite
Mineral CaAl12O19
About it
Black to reddish-brown hexagonal plates in metamorphosed limestones of Madagascar, and tiny grains in some of the oldest meteorite inclusions. Named for Paul Hibon, who found it in Madagascar.
- Type
- Mineral
- Group
- Oxide, magnetoplumbite group
- Formula
- CaAl12O19
- Hardness (Mohs)
- 7.5–8
- Specific gravity
- 3.8–3.9
- Streak
- reddish brown
- Lustre
- vitreous (glassy), submetallic
- Crystal system
- Hexagonal
- Colours
- black, brownish black, reddish brown, orange
- Transparency
- opaque, translucent
- Cleavage and fracture
- good basal
Typical values: real specimens vary. For more, see mindat.org.