Conchoidal, Brittle, Conchoidal, Brittle, Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Uneven, Uneven, Management Team (2012), Conchoidal, Brittle
PbSO 4Michael OâDonoghue , Gems, Sixth edition (2006) More from other references
Fe 3O 4Ulrich Henn and Claudio C.