Hibonite

Hibonite is named after Paul Hibon, a French prospector who discovered the mineral in Madagascar.

Hibonite is a very rare gem. Stones which are large enough or transparent enough for faceting are very sparse.

Hibonite is slightly radioactive.
Photos of natural/un-cut material from mindat.org
Physical Properties of Hibonite
Mohs Hardness7.5 to 8
Anthony et al, Handbook of mineralogy (2001)
Specific Gravity3.84
Anthony et al, Handbook of mineralogy (2001)
Cleavage QualityGood
Anthony et al, Handbook of mineralogy (2001)
FractureSub-Conchoidal
Anthony et al, Handbook of mineralogy (2001)
Optical Properties of Hibonite
Refractive Index1.79 to 1.807
Anthony et al, Handbook of mineralogy (2001)
Optical CharacterUniaxial/-
Anthony et al, Handbook of mineralogy (2001)
PleochroismBrownish gray - gray
Anthony et al, Handbook of mineralogy (2001)
Colour
Colour (General)Brownish black to black; reddish brown in thin fragments.
Anthony et al, Handbook of mineralogy (2001)
TransparencyTranslucent
Anthony et al, Handbook of mineralogy (2001)
LustreVitreous
Anthony et al, Handbook of mineralogy (2001)
Crystallography of Hibonite
Crystal SystemHexagonal
Anthony et al, Handbook of mineralogy (2001)
HabitPrisms, platy or steep pyramidal, to 4 cm.
Anthony et al, Handbook of mineralogy (2001)
Geological Environment
Where found:In metamorphosed limestone, pyroxenite, gneiss, and granulite of the amphibolite to granulite facies; also alluvial. A common accessory in Ca–Al-rich inclusions in some carbonaceous chondrites.
Anthony et al, Handbook of mineralogy (2001)
Further Information
Mineral information:Hibonite information at mindat.org
Significant Gem Localities
Myanmar
 
  • Mandalay Region
    • Pyin-Oo-Lwin District
        • Kyauk-Pyat-That
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