UnevenArthur Thomas, Gemstones (2009) Tough, UnevenArthur Thomas, Gemstones (2009) Tough, Brittle, Uneven
Uneven, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Mn 8Si 6O 15(OH,Cl) 10Ulrich Henn and Claudio C.
Ca 3Al 2(SO 4)(F,OH) 10Ulrich Henn and Claudio C.