Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Conchoidal, Uneven, ConchoidalArthur Thomas, Gemstones (2009), Brittle
Na 3(Na,K)Al 4Si 4O 16Ulrich Henn and Claudio C.
(Cs,Na)(AlSi 2O 6) · 0.5H 2OWalter Schumann , Gemstones of the world (2001) More from other references