Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Uneven, Subconchoidal, Uneven, Subconchoidal, Conchoidal, Brittle
Ca 3Al 2(SiO 4) 3Arthur Thomas , Gemstones (2009)
NaAlSi 2O 6 · H 2OMichael OâDonoghue , Gems, Sixth edition (2006) More from other references