ConchoidalWalter Schumann, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Splintery
Uneven, Uneven, Conchoidal, Uneven, Gems, Sixth Edition (2006)
{100} Distinct, {110} Distinct
Perfect on {001}, good on {010}
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
(Na,Ca)Al1-2Si3-2O8