Claude François Geoffroy (1729 – 18 June 1753) was a French chemist. In 1753 he proved the chemical element bismuth to be distinct from lead, becoming the official discoverer of the element. Before this time, bismuth-containing minerals were frequently misidentified as either lead, tin, or antimony ores. His observations on the matter were published in the Mémoires de l’académie française in 1753. He became a master apothecary in 1748, and in 1752 he was admitted to the Académie des sciences as a supernumerary adjoint chemist. He died on 18 June 1753, (age 23 or 24).