UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Uneven
Conchoidal, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Conchoidal, Brittle
FeS 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
CuSiO 2(OH) 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references