Transparency crystals are transparent to translucent. Crystal Habits include long, somewhat prismatic or tabular crystals with a typically dominant pinacoid that the crystal is often flattened against. The terminations are usually poorly developed. Also massive or granular. Cleavage good in one direction lengthwise.
Fracture is uneven to conchoidal.
6 - 7 Specific Gravity is approximately 3.3 Streak is white. Also strongly pleochroic with an index of refraction of 1.68 - 1.72. Associated Minerals include calcite , biotite , hornblende , quartz , corundum , andradite garnets and other metamorphic minerals. Best Field Indicators only one direction of cleavage, associations, color, pleochroism and hardness.