When it occurs in its elemental form in nature, bismuth is a white, brittle metal, but oxidation can give it a pink tint. However, most of the time bismuth is found in minerals such as bismuthinite and bismite. There are natural bismuth deposits, the largest of which are in Bolivia, but the metal is more often produced as a by-product of mining and processing lead and tungsten.
Bismuth has several characteristics that make it unique. It is repelled by a magnetic field, expands when frozen, has a low melting point and has one of the lowest levels of thermal conductivity. For a heavy metal, its toxicity is unusually low. Now that we are aware of the dangers of lead, bismuth alloys are often used as a replacement.