Splintery, UnevenArthur Thomas, Difficult, Fibrous
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
NaAlSi 2O 6Ulrich Henn and Claudio C.
Cu 3(OH) 2(CO 3) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references