Chemical Properties
Glauberite is a calcium-sodium sulfate mineral. It crystallizes monoclinically, with plate-like or short columnar crystals; aggregates are granular, scaly, or reniform. It is colorless, gray, white, or light yellow. Its streak is white. It has a vitreous or waxy luster and is brittle. Its hardness is 2.5-3 and its density is 2.75-2.85 g/cm??. It has a slightly salty taste. It dissolves slowly in water, decomposing into fine, needle-shaped gypsum crystals or glauberite. It is readily soluble in hydrochloric acid. Its flame is yellow. Upon contact with water, glauberite changes from a vitreous luster to an earthy luster, and its surface is covered with a "hoarfrost." This mineral is widely distributed in marine and lacustrine salt deposits, coexisting with rock salt, glauberite, gypsum, leonite, and polyhalite. Glauberite is unstable under weathering conditions, and secondary forms form when anhydrite is replaced by a solution containing Na??SO??.
Physical properties
Habit: tabular, prismatic.
Color: yellow, reddish gray, or red.
Luster: vitreous (glassy).
Diaphaneity: transparent to translucent.
Streak: white.
Fracture: brittle–conchoidal.
Cleavage: [001] perfect.
Occurrence: dry salt-lake beds in desert climates.
