ConchoidalWalter Schumann, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Splintery
UnevenArthur Thomas, Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Conchoidal, Brittle
{100} Distinct, {110} Distinct
Perfect on {110} at 56° and 124°; partings on {010} and {100}
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.