Uneven, Conchoidal, ConchoidalArthur Thomas, Gemstones (2009)
ConchoidalWalter Schumann, ConchoidalWalter Schumann, Gemstones of the world (2001) More from other references, Splintery
Perfect {010} imperfect {100}
{100} Distinct, {110} Distinct
Ca2Al3(SiO4)3(OH)
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