Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle
Uneven, Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Uneven, Subconchoidal, Brittle, Metallic, Brittle, Metallic
Al 6B 5O 15(F,OH) 3Ulrich Henn and Claudio C.
Zn 2(AsO 4)(OH)Michael OâDonoghue , Gems, Sixth edition (2006)