Uneven, Subconchoidal, Uneven, Subconchoidal, Splintery, UnevenArthur Thomas, Gemstones (2009)
Uneven, Brittle, Metallic, Brittle, Metallic
Al 2SiO 5Michael OâDonoghue , Gems, Sixth edition (2006) More from other references
NaNa2(Fe++4Fe+++)Si8O22(OH)2