Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle
Uneven, Uneven, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Brittle, Conchoidal
Al 6B 5O 15(F,OH) 3Ulrich Henn and Claudio C.
PbCO 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references