Uneven, Brittle, Metallic, Brittle, Metallic
Uneven, Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Uneven, Subconchoidal, Brittle, Metallic, Brittle, Metallic
NaNa2(Fe++4Fe+++)Si8O22(OH)2
Zn 2(AsO 4)(OH)Michael OâDonoghue , Gems, Sixth edition (2006)