ConchoidalWalter Schumann, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Splintery
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009)
Na 4Al 3Si 9O 24Cl to Ca 4Al 6Si 6O 24(CO 3,SO 4)Walter Schumann , Gemstones of the world (2001) More from other references
Ca 2Mg 5Si 8O 22(OH) 2Ulrich Henn and Claudio C.