Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle
Uneven, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
KAlSi 2O 6Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Ca 3Al 2(SO 4)(F,OH) 10Ulrich Henn and Claudio C.