Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009)
Na 3(Na,K)Al 4Si 4O 16Ulrich Henn and Claudio C.
Ca 2Mg 5Si 8O 22(OH) 2Ulrich Henn and Claudio C.