WITHERITE (from the name of the discoverer, William Withering, the English Medical Doctor, botanist, and mineralogist of the 18th century * EN: witherite; DE: Witherit; FR: witherite; ES: witherita; RU: витерит) is the mineral of the class of carbonates, BaCO3. Witherite sometimes contains the impurities of Sr (up to 1.5%), Ca, less often Mg, Cu (< 1%). Witherite crystallizes into the rhombic crystal system. The crystal structure is sub-layered (similar to aragonite). The crystals are rare; witherite forms the pseudohexagonal trillings, of the flattened, lenticular, sometimes prismatic crystal habit; more often, witherite may be encountered in the form of the spherical and uviform isolates, columnar and coarse fibrous masses, radiant and dense granular aggregates. The colour is white to colourless, sometimes with the yellowish, brownish, and greenish tinges. Witherite is transparent or translucent. Witherite is brittle. The cleavage is good along one direction. The hardness is 3.5. The density is 4300 kilograms per cubic metre.

Witherite is the comparatively rare low-temperature hydrothermal mineral. In case of the large clusters of witherite (the Settingston, Alston Moor, and other deposits within the Northern England), it is being developed as the raw material for the obtainment of barium and its compounds, as the weighting agent for the drilling fluids, for the producing of the special plaster, which is impervious to the X-rays. The ores of witherite are beneficiated analogously to the barite ores.