Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Brittle, Metallic
TiO 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
CuSMichael OâDonoghue , Gems, Sixth edition (2006) More from other references