Conchoidal, Brittle, Conchoidal, Brittle, Conchoidal, Brittle
Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
(Mg,Fe2+ ) 2(Mg,Fe2+ ) 5Si 8O 22(OH) 2Anthony et al , Handbook of mineralogy (2001)
Na 3(Na,K)Al 4Si 4O 16Ulrich Henn and Claudio C.