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Hibonite, 1.6 cm (0.63 in) sharp and lustrous crystal from Esiva eluvials, Maromby Commune, Amboasary District, Anosy (Fort Dauphin) Region, Tuléar (Toliara) Province, Madagascar
CategoryOxide minerals
(repeating unit)
IMA symbolHbn[1]
Strunz classification4.CC.45
Crystal systemHexagonal
Crystal class
  • Dihexagonal dipyramidal (6/mmm)
  • H-M symbol: (6/m 2/m 2/m)
Space groupP63/mmc
Unit cella = 5.56, c = 21.89 [Å]; Z = 2
ColorBrownish black to black; reddish brown in thin fragments; blue in meteorite occurrence
Crystal habitPrismatic platy to steep pyramidal crystals
Cleavage{0001} good, {1010} parting
Mohs scale hardness7+12–8
Streakreddish brown
Specific gravity3.84
Optical propertiesUniaxial (-)
Refractive indexnω = 1.807(2), nε = 1.79(1)
PleochroismO = brownish gray; E = gray

Hibonite is a mineral with the chemical formula (Ca,Ce)(Al,Ti,Mg)12O19, occurring in various colours, 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 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.[4] Hibonites were among the first minerals to form as the disk of gas and dust swirling around the young sun cooled.[5]

A very rare gem, hibonite was discovered in 1953 in Madagascar by Paul Hibon, a French prospector.[6]



Hibonite can vary in colour, from a bright blue, to green, to orange, to a nearly black deep brown. The colour is related to the degree of oxidation; meteoritic hibonite tends to be blue.[7]

See also



  1. ^ Warr, L.N. (2021). "IMA–CNMNC approved mineral symbols". Mineralogical Magazine. 85 (3): 291–320. Bibcode:2021MinM...85..291W. doi:10.1180/mgm.2021.43. S2CID 235729616.
  2. ^ "Handbook of Mineralogy" (PDF).
  3. ^ "Hibonite: Hibonite mineral information and data". www.mindat.org.
  4. ^ "IMA Mineral List with Database of Mineral Properties". rruff.info.
  5. ^ "A Year in Review and a Look to the Future". Field Museum of Natural History. January 11, 2019. Retrieved 4 December 2021.
  6. ^ "Hibonite gemstone information". www.gemdat.org.
  7. ^ Ihinger, Phillip D.; Stolper, Edward (May 1986). "The color of meteoritic hibonite: an indicator of oxygen fugacity". Earth and Planetary Science Letters. 78 (1): 67–79. Bibcode:1986E&PSL..78...67I. doi:10.1016/0012-821X(86)90173-1.