Cobalt

Cobalt is a chemical element with the symbol Co. Like nickel, cobalt is found in the Earth's crust only in chemically combined form, save for small deposits found in alloys of natural meteoric iron. The free element, produced by reductive smelting, is a hard, lustrous, silver-gray metal. A lustrous, silvery-blue metal. It is magnetic.

Cobalt, like iron, can be magnetised and so is used to make magnets. It is alloyed with aluminium and nickel to make particularly powerful magnets.

Other alloys of cobalt are used in jet turbines and gas turbine generators, where high-temperature strength is important. Cobalt salts have been used for centuries to produce brilliant blue colours in paint, porcelain, glass, pottery and enamels.

Radioactive cobalt-60 is used to treat cancer and, in some countries, to irradiate food to preserve it.