Uneven, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Uneven, Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Uneven, Subconchoidal, Brittle, Metallic, Brittle, Metallic
(Mg,Fe) 5(SiO 4) 2(F,OH) 2Ulrich Henn and Claudio C.
Zn 2(AsO 4)(OH)Michael OâDonoghue , Gems, Sixth edition (2006)