UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Uneven
Gems, Conchoidal, Brittle
FeS 2Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references
Ca 3Ti4+2(Fe3+2Si)O 12Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references