For sodium perborate, see Sodium perborate. Borax, also known as sodium borate, sodium tetraborate, or disodium tetraborate, is an important boron compound, a mineral, and a salt of boric acid. Powdered borax is white, consisting of soft colorless crystals that dissolve easily in water. Borax has a wide variety of uses. It is a component of many detergents, cosmetics, and enamel glazes.