Uneven, UnevenArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
(Na,Ca) 8Al 6Si 6O 24(SO 4,S,Cl) 2Ulrich Henn and Claudio C.
Na 3(Na,K)Al 4Si 4O 16Ulrich Henn and Claudio C.