Thenardite is a mineral composed primarily of sodium sulfate (Na2SO4). It typically forms in arid environments and can be found in evaporite deposits, where water evaporates and leaves behind various salts. The mineral is usually white or colorless and has a crystalline structure. This mineral is named after the French chemist Louis Thenard, who studied it in the early 19th century. Thenardite is soluble in water and can be used in various industrial applications, including the production of glass, detergents, and as a drying agent in chemical processes.