Conchoidal, Brittle, Conchoidal, Brittle, Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Uneven, Uneven, Management Team (2012), Conchoidal, Brittle
Fe 3Al 2(SiO 4) 3Arthur Thomas , Gemstones (2009)
Fe 3O 4Ulrich Henn and Claudio C.