Barium sulfate is a white crystalline solid that is odorless and insoluble in water. It occurs as the mineral barite, which is the main commercial source of barium and materials prepared from it. It is used for pigments in paints, paper brightener, a filler for plastics to increase its density, as well as in a variety of other specialty industries.
Barium sulfate also has a niche market in in soil testing. Tests are often used to find the soil pH. Barium sulfate added to a mixture binds with particles, making them heavier so they fall to the bottom, leaving a clearer solution.