Barium sulfate Barium sulfate Barium sulfate (or sulphate) is the inorganic compound with the chemical formula BaSO. It is a white crystalline solid that is odorless and insoluble in water. It occurs as the mineral barite, which is the main commercial source of barium and materials prepared from it. The white opaque appearance and its high density are exploited in its main applications. About 80% of the world's barium sulfate production, mostly purified mineral, is consumed as a component of oil well drilling fluid. It increases the density of the fluid, increasing the hydrostatic pressure in the well and reducing the chance
Pewter known as "trifling metal" or "trifle", was used for holloware and is made up of fine metal with approximately 4% lead. The last type of pewter, known as "lay" or "ley" metal, was used for items that were not in contact with food or drink. It consisted of tin with 15% lead. These three alloys were used with little variation until the 20th century. Older pewters with higher lead content are heavier, tarnish faster, and oxidation gives them a darker silver-gray color. Pewters containing lead are no longer used in items that will come in contact with the human body