Luster is pearly to vitreous or dull. Crystals are transparent to mostly translucent. Crystal System is orthorhombic. Crystal Habits include flat tabular or lamellar crystals. Cleavage is good in one direction.
Fracture is uneven.
Streak is white. Displays iridescence between cleavage layers and lamellar twining is common. Best Field Indicators are crystal habit, color, cleavage, hardness and locality.