Irregular/uneven, UnevenArthur Thomas, Gemstones (2009)
Uneven, Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Uneven, Subconchoidal, Brittle, Metallic, Brittle, Metallic
CaAl 2Si 4O 12 -6H 2OArthur Thomas , Gemstones (2009)
Zn 2(AsO 4)(OH)Michael OâDonoghue , Gems, Sixth edition (2006)