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