readily altered to barium sulfate by the action of water containing calcium sulfate in solution and crystals are therefore frequently encrusted with barytes. It is the chief source of barium salts and is mined in considerable amounts in Northumberland. It is used for the preparation of rat poison, in the manufacture of glass and porcelain, and formerly for refining sugar. It is also used for controlling the chromate to sulfate ratio in chromium electroplating baths. See also List of minerals List of minerals named after people References External links Barium minerals Carbonate minerals Orthorhombic minerals Minerals in space group 62 Luminescent minerals Aragonite group