Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
Conchoidal, Splintery, Fibrous
Perfect on {010}, distinct on {100}
CaSO 4 -2(H 2O)Arthur Thomas , Gemstones (2009)
ConchoidalWalter Schumann
Perfect on {010}, good on {100}
Be 2BO 3(OH)Ulrich Henn and Claudio C.