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.