Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle, Conchoidal, Brittle
Gemstones (2009), UnevenArthur Thomas, Gemstones (2009), Brittle, Uneven
(Na,Ca,K) 8(Si,Al) 12O 24(SO 4,Cl,CO 3) 3(H 2O)Arthur Thomas , Gemstones (2009)
ThCa 2Si 8O 20Walter Schumann , Gemstones of the world (2001) More from other references