Bismuth, chemical element, symbol Bi; for physical constants see Periodic Table. Bismuth was known to the ancients and in early times was confused with tin and lead. It was shown to be distinct from lead in 1753 by Claud J. Geoffroy. Bismuth is sometimes found native, as the minerals bismite and bismuthinite. It is obtained as a byproduct of the refining of lead, copper, and tin. Bismuth is a grayish-white, hard, brittle, low-melting metal. It is the most diamagnetic of all metals and has the highest Hall effect of any metal. It has a low thermal conductivity and a high electrical resistance. Bismuth forms low-melting alloys that are widely used in fire detection and fire extinguishing systems. Bismuth and its compounds are used in powerful magnets and, in medicine, as antisyphilitics and anti-infectives.