Uneven, Conchoidal, Brittle, Metallic, ConchoidalArthur Thomas, Gemstones (2009)
Gemstones (2009), Flexible Flexible fragments.
Ca 3Cr 2(SiO 4) 3Ulrich Henn and Claudio C.
Al 2Si 4O 10(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references