Uneven, Conchoidal, Brittle, Metallic, ConchoidalArthur Thomas, Gemstones (2009)
Uneven, Uneven, Gemstones of the world (2001) More from other references
Ca 3Cr 2(SiO 4) 3Ulrich Henn and Claudio C.
Ca 10Mg 2Al 4(SiO 4) 5(Si 2O 7) 2(OH) 4Ulrich Henn and Claudio C.