Conchoidal, Brittle, Conchoidal, UnevenArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Uneven, Brittle, Metallic, Brittle, Metallic, Brittle, Metallic
Rare tabular and prismatic crystals. Usually occurs as fibrous, parallel veins that break off into cleavage fragments.
Good on {110}, (110) ^ (1 1 0) ≈87°; parting on {100}
CaSO 4Michael OâDonoghue , Gems, Sixth edition (2006) More from other references
(Na,Fe,Ca)Si 2O 6Ulrich Henn and Claudio C.