Crystals are transparent to translucent. At times the pyramids become prominant and psuedo-dipyramidal crystal habits are seen, sometimes because of twinning. Prismatic faces are also seen and can make psuedo-cubic crystals. Also encrusting and cavernous aggregates due to intergrowth of crystal plates. Cleavage is perfect in one direction.
Fracture is conchoidal.
Hardness is 3. Streak is white. Associated Minerals are mimetite , limonite , smithsonite , vanadinite and galena . Best Field Indicators are crystal habit, color, density and luster.