ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
Subconchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle
[C,H,O]
(Fe,Mg,Zn) 2Al 9(Si,Al) 4O 22(OH) 2Ulrich Henn and Claudio C.