Barite
Barite (barium sulfate, BaSO₄) is a deceptive mineral—it is much heavier than it looks. Barite found in Illinois is generally white or light colored, and, although some of it looks rather like white limestone, it is more than half again as heavy as limestone. Barite’s unusual weight is responsible for one of its major uses—as a constituent of drilling muds for the oil industry. These muds are a mixture of clay, water, and a weighting material such as barite. They are used in various ways in the drilling of oil wells by rotary drills. Barite also is an important raw material for the manufacture of chemicals.
Barite is found in Hardin and Pope Counties, the site of the fluorspar industry. According to studies made by Survey geologists, the barite occurs both as veins and beds associated with fluorspar, but its distribution is irregular and the deposits are of limited size. A barite mine is said to have been worked years ago, and more recently comparatively small tonnages have been taken from open pits. Future exploration in southern Illinois may reveal deposits of barite that will be profitable to mine.