Musgravite

Musgravite
Musgravite from Sri Lanka
General
CategoryOxide minerals
Formula
(repeating unit)
(Mg,Fe,Zn)2BeAl6O12
Strunz classification04.FC.25
Crystal systemTrigonal
Identification
ColorGrey green to green
FractureConchoidal
Mohs scale hardness8–8.5
LusterVitreous
DiaphaneityTransparent
Specific gravity3.62–3.68
Optical propertiesUniaxial
Refractive indexnω = 1.739, nε = 1.735
Birefringenceδ = 0.014 to 0.016
References[1][2]

Musgravite or magnesiotaaffeite-6N’3S is a rare oxide mineral used as a gemstone. Its type locality is the Ernabella Mission, Musgrave Ranges, South Australia, for which it was named following its discovery in 1967.[2] It is a member of the taaffeite family of minerals,[2][1] and its chemical formula is Be(Mg, Fe, Zn)2Al6O12. Its hardness is 8 to 8.5 on the Mohs scale.[2] Due to its rarity, the mineral can sell for roughly USD$35,000 per carat.

See also

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References

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