Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009)
Na 3(Na,K)Al 4Si 4O 16Ulrich Henn and Claudio C.
Ca 5(F,Cl)(PO 4) 3Arthur Thomas , Gemstones (2009)