Lamellar twinning is common. Cleavage is poor in one direction, basal. Fracture is subconchoidal. Hardness is 6. Specific Gravity is 3.2 - 3.4 Streak is white.
Crystals are pleochroic from yellow to colorless.
Associated Minerals include humite , talc , geikielite , lazurite , dolomite and calcite . Best Field Indicators are color, associations, fluorescence, environment of formation and hardness.