Subconchoidal, Conchoidal, Brittle, ConchoidalArthur Thomas, Gemstones (2009)
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