Category Oxide minerals Strunz classification 4.CC.45 Space group P63/mmc | Formula
(repeating unit) (Ca,Ce)(Al,Ti,Mg)12O19 Crystal system Hexagonal | |
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Crystal class Dihexagonal dipyramidal (6/mmm)
H-M symbol: (6/m 2/m 2/m) | ||
Hibonite ((Ca,Ce)(Al,Ti,Mg)12O19) is a brownish black mineral with a hardness of 7.5-8.0 and a hexagonal crystal structure. It is rare, but is found in high-grade metamorphic rocks on Madagascar. Some presolar grains in primitive meteorites consist of hibonite. Hibonite also is a common mineral in the Ca-Al-rich inclusions (CAIs) found in some chondritic meteorites. Hibonite is closely related to hibonite-Fe (IMA 2009-027, ((Fe,Mg)Al12O19)) an alteration mineral from the Allende meteorite.
A very rare gem, Hibonite was discovered in Madagascar by Paul Hibon, a French prospector.
References
Hibonite Wikipedia(Text) CC BY-SA