The discovery, and use of iron predates written history. Iron is a relatively abundant element in the universe. It is found in the sun, and in many stars in considerable quantities. Iron, the fourth most abundant element, is the major component of the earth's core, and its crust. Iron is a vital constituent of plant and animal life, even appearing in hemoglobin.
Pure iron is very reactive chemically, and rapidly corrodes in moist air and elevated temperatures.
Iron is the cheapest, most abundant of all metals, and its alloys with ather metals are very useful. Pig iron, an alloy containing carbon, sulfur, silicon, manganese, and phosphorous is used to produce steel.