Tenacity
Solubility
Durability
Specific Gravity
Fracture
Cleavage
Mohs Hardness
Chemical Composition
SiO2, Al2O3, FeO, MgO, CaO, K2O, Na2O
{110} Perfect, {???} Distinct, {???} Distinct
(Mg,Fe2+ ) 2(Mg,Fe2+ ) 5Si 8O 22(OH) 2Anthony et al , Handbook of mineralogy (2001)