Irregular/uneven, Brittle, Metallic
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle, Conchoidal, Brittle
Ca6(Al,Si)2(SO4)2B(OH)4(OH,O)12•26(H2O)
(Na,Ca,K) 8(Si,Al) 12O 24(SO 4,Cl,CO 3) 3(H 2O)Arthur Thomas , Gemstones (2009)