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