Conchoidal, Brittle, Conchoidal, UnevenArthur Thomas, Gemstones (2009), Brittle, Conchoidal
Uneven, Uneven, ConchoidalAnthony et al, Handbook of mineralogy (2001), Conchoidal, Brittle
Rare tabular and prismatic crystals. Usually occurs as fibrous, parallel veins that break off into cleavage fragments.
{???} Distinct, {???} Indistinct
CaSO 4Michael OâDonoghue , Gems, Sixth edition (2006) More from other references
3CaAl 2Si 2O 8 · CaCO 3Anthony et al , Handbook of mineralogy (2001)