Baryte, or barite, (BaSO4) is a mineral consisting of barium sulfate. The baryte group consists of baryte, celestine, anglesite and anhydrite. Baryte itself is generally white or colorless, and is the main source of barium. Baryte and celestine form a solid solution (Ba,Sr)SO4.
The radiating form, sometimes referred to as Bologna Stone, attained some notoriety among alchemists for the phosphorescent specimens found in the 17th century near Bologna by Vincenzo Casciarolo. The term "primary baryte" refers to the first marketable product, which includes crude baryte (run of mine) and the products of simple beneficiation methods, such as washing, jigging, heavy media separation, tabling, flotation. Most crude baryte requires some upgrading to minimum purity or density. Baryte that is used as an aggregate in a "heavy" cement is crushed and screened to a uniform size. Most baryte is ground to a small, uniform size before it is used as a filler or extender, an addition to industrial products, or a weighting agent in petroleum well drilling mud.