Carl Josef Bayer (also Karl Bayer, March 4, 1847 – October 4, 1904) was an Austrian chemist who invented the Bayer process of extracting alumina from bauxite, essential to this day to the economical production of aluminium. In the mid-19th-century, aluminium was so precious that a bar of the metal was exhibited alongside the French Crown Jewels at the Exposition Universelle in Paris 1855. Along with the Hall–Héroult process, Bayer's solution caused the price of aluminium to drop about 80% in 1890 from what it had been in 1854.