All may form as efflorescent crusts on the walls of caves and mines or in soils in arid regions. Color is gray, colorless, white, pale brown or yellowish. Luster is vitreous. Crystals are transparent to translucent. Crystal Habits include prismatic to blocky crystals, but usually massive, fibrous or columnar.
Cleavage is perfect in one direction and poor in two others.
Fracture is subconchoidal to uneven. Hardness is 2.5 - 3. Streak is white. Has an alkaline taste. Associated Minerals include hanksite , gaylussite , halite , pirssonite , northupite , nahcolite , borax and calcite .