Conchoidal, Brittle, Conchoidal, UnevenArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
CaSO 4Michael OâDonoghue , Gems, Sixth edition (2006) More from other references
CaBePO 4(F,OH)Ulrich Henn and Claudio C.