Barium Sulfate is a compound used as an x-ray contrast medium that occurs in nature as the mineral barite. It is also used in various manufacturing applications and mixed into heavy concrete to serve as a radiation shield. Barium Sulfate is the sulfate salt of barium, an alkaline, divalent metal. Barium sulfate is quite insoluble in water, and is used as a radiopaque agent to diagnose gastrointestinal medical conditions. Barium sulfate is taken by mouth or given rectally.