Colors include dark yellow, yellow-brown and brown. Luster is vitreous. Specimens are transparent to translucent. Crystal Habits include equidimensional tabular, bladed or platy crystals. Aggregates include lamellar, parallel growth and fibrous habits.
Cleavage is good in two directions at right angles.
Fracture is conchoidal. Hardness is 4.5 - 5. Streak is white. Associated Minerals include quartz , feldspars , lithiophilite , chlorite , pyrite , hureaulite and triphylite . Best Field Indicators are crystal habit, color, associations, localities and density.