Typically found in England (Cumbria), Morocco, China, and the United States, it owes its name to the Greek word “barys” (heavy), due to its unusually high density for a nonmetallic mineral. It forms both in sedimentary environments—through evaporitic precipitation or as diagenetic cement in marine basins—and in low- to medium-temperature hydrothermal veins, often as a gangue mineral associated with metal sulfides (galena, sphalerite, chalcopyrite). It crystallizes in tabular or prismatic forms, with characteristic perfect cleavage along the basal plane. Hardness 3–3.5 on the Mohs scale; very high density for a non-metallic mineral (4.3–4.5 g/cm³); color ranges from colorless to white, yellow, light blue, or brown, depending on impurities.

An industrial mineral of great importance as an additive in oil drilling mud (due to its weight), as radiation shielding (in hospital construction), and as a filler in paints and plastics; It is prized by collectors for its “rose-like” aggregates (desert rose) and for its well-formed, transparent tabular crystals.