Chemical Formula: (Ca,Ce)Al12O19
Locality: Esiva, near Taolanaro (Fort Dauphin), and near Ambindandrakemba, Madagascar.
Name Origin: Named for Paul Hibon, who discovered the mineral.
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.
Physical Properties
Cleavage: {0001} Good, {1010} Parting
Color: Black, Black, Reddish brown.
Density: 3.84
Diaphaneity: Opaque
Fracture: Sub Conchoidal – Fractures developed in brittle materials characterized by semi-curving surfaces.
Hardness: 7.5-8
Luster: Metallic
Streak: reddish brown
Photos :
Al12O19 Locality: Esiva, near Taolanaro (Fort Dauphin), and near Ambindandrakemba, Madagascar. Name Origin: Named for Pa){kind=link}