Barium sulfate (BaSO4) is the barium salt of sulfuric acid. The term “barium” is derived from the Greek word barys = heavy, which indicates the element’s high atomic weight. Barium sulfate is practically insoluble in water, acids (an exception being hot concentrated sulfuric acid), and bases. Due to its extremely low water solubility, barium sulfate, as compared to other barium compounds, is non-toxic.
Today, barite (heavy spar) is the only technically used base material for all barium compounds and for barium metal . The major quantity of the barium sulfate that is won by mining is used in oil and natural gas production to obtain high-density drilling fluids for flotation which keeps the boreholes free of rock.