Jern

Jern is the Norwegian word for iron, the chemical element with symbol Fe and atomic number 26. It is a metal that occurs widely in the Earth's crust and forms the basis of many alloys, most notably steel.

The term jern derives from Old Norse járn, related to Danish jern and Swedish järn.

Iron is a transition metal. In pure form it is silvery-gray, relatively soft, and highly reactive with air. It is ferromagnetic at room temperature, with a density of about 7.87 g/cm³ and a melting point of 1,538°C.

Most iron occurs in minerals such as hematite and magnetite. Ore is extracted and smelted with carbon to produce pig iron, which is refined into steel or cast iron. Large amounts of iron are also present in Earth’s core, mainly in a nickel-iron alloy.

Iron and steel are among the most important construction and manufacturing materials. Cast iron is used for pipes and blocks; wrought iron (and especially steel) is used for structural beams, machinery, and tools.

The use of iron dates to the Iron Age, when tools and weapons became more common. Modern steelmaking developed through the 19th century and has since enabled a wide range of innovations.