Bismuth is a brittle, crystalline, white metal with a slight pink tinge. Bismuth metal is brittle and so it is usually mixed with other metals to make it useful. Its alloys with tin or cadmium have low melting points and are used in fire detectors and extinguishers, electric fuses and solders.
Bismuth is used in metal alloys with other metals such as iron, to create alloys to go into automatic sprinkler systems for fires. It was also used to make bismuth bronze which was used in the Bronze Age.
Bismuth is seen as the least toxic heavy metal for humans and is widely used in medical applications for its good antibacterial properties. Bismuth-containing pharmaceuticals are most commonly used in the eradication of Helicobacter pylori, the causative agent for diseases like gastritis, peptic ulcer and even gastric cancer.
Bismuth oxychloride (BiOCl) is occasionally used in cosmetics, as a pigment in paint for eye shadows, hair sprays and nail polishes. This compound is found as the mineral bismoclite and in crystal form contains layers of atoms that refract light chromatically, resulting in an iridescent appearance similar to nacre of pearl.
Bismuth is also used as a lead replacement due to their density difference being very small.
Bismuth is also used in brass alloys, thermocouples, alloys for drop hammer and embossing dies, fuel tank safety plugs alloys, catalysts for making acrylic fibers (various chemicals), bismanol permanent magnets (Manganese Bismuth - MnBi), low melt alloys (eg Wood's metal), malleable iron and machine able aluminum or copper, and in lead-acid batteries