Irregular/uneven, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Uneven, Subconchoidal, Uneven, Subconchoidal, Splintery, UnevenArthur Thomas, Gemstones (2009)
Perfect on {10 1 0}, poor on {0001}
Good on {110}, poor on {100}
Na 2Ca 2Al 6Si 6O 24(CO 3) 2Walter Schumann , Gemstones of the world (2001) More from other references
Al 2SiO 5Michael OâDonoghue , Gems, Sixth edition (2006) More from other references