Uneven, Conchoidal to uneven, Brittle, Metallic, Uneven, ConchoidalWalter Schumann, Brittle, Metallic
Conchoidal, ConchoidalArthur Thomas, Gemstones (2009), Conchoidal, Brittle, Conchoidal, Brittle
BeAl 2 O 4
(Na,Ca,K) 8(Si,Al) 12O 24(SO 4,Cl,CO 3) 3(H 2O)Arthur Thomas , Gemstones (2009)