Conchoidal, ConchoidalAnthony et al, Handbook of mineralogy (2001), Brittle
Uneven, Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Uneven, Subconchoidal, Brittle, Metallic, Brittle, Metallic
SiCArthur Thomas , Gemstones (2009)
Zn 2(AsO 4)(OH)Michael OâDonoghue , Gems, Sixth edition (2006)