Uneven, Brittle, Metallic, Brittle, Metallic, Brittle, Metallic
ConchoidalArthur Thomas, Gemstones (2009), ConchoidalArthur Thomas, Gemstones (2009), Brittle, Conchoidal
(Na,Fe,Ca)Si 2O 6Ulrich Henn and Claudio C.
Na 2Ca 2(CO 3) 3Michael OâDonoghue , Gems, Sixth Edition (2006) More from other references