Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Uneven
CaCO 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
FeS 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references