Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle
Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
(Cs,Na)(AlSi 2O 6) · 0.5H 2OWalter Schumann , Gemstones of the world (2001) More from other references
Ca 3Al 2(SiO 4) 3Arthur Thomas , Gemstones (2009)