Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
slightly water soluble and in hot hydrochloric acid
Subconchoidal, Uneven, ConchoidalWalter Schumann
Octahedral, perfect on {111}, parting on {011}
SiO2, Al2O3, FeO, MgO, CaO, K2O, Na2O