Uneven, Conchoidal, Brittle, Metallic, ConchoidalArthur Thomas, Gemstones (2009)
Subconchoidal, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Conchoidal
Ca 3Cr 2(SiO 4) 3Ulrich Henn and Claudio C.
LiAlSi 4O 10Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references