It is a highly corrosive, strong mineral acid, and therefore has major industrial use. It is found naturally in gastric acid. Historically called muriatic acid and spirit of salt, hydrochloric acid was produced from vitriol and common salt. The alchemist Jabir ibn Hayyan first formally decribed it in the eighth century. Throughout the Middle Ages, it was used by alchemists in the quest for the philosopher's stone, and later by European scientists including Glauber, Priestley, and Davy. With major production starting in the Industrial Revolution, hydrochloric acid is used in the chemical industry as a chemical reagent in the large-scale production of vinyl chloride for PVC plastic, and MDI/TDI for polyurethane.