Color is white or gray, sometimes with tints of red-brown or yellow. Luster is vitreous. Transparency crystals are translucent to transparent. Crystals are rare, but when found are in the form of rhombohedrons similar to calcite's crystals. Cleavage is perfect in three directions forming rhombohedrons.
Fracture is conchoidal.
Hardness is 1.5 - 2. Streak is white. Associated Minerals gypsum , halite and other arid region minerals. Deliquescent, slightly sectile, very soluble in water and gives a yellow flame test result. Best Field Indicators are crystal habit, flame test, solubility, deliquescence, hardness, occurrence and cleavage.