Iron (Fe) is a lustrous, ductile, malleable, silver-gray metal. A good conductor of heat and electricity, it is attracted by a magnet and is itself easily magnetized. Iron is abundant throughout the universe. It is found in many stars, including the sun. It is the fourth most common element in the earth's crust, of which it constitutes about 5 percent by weight, and is believed to be the main component of the earth's core. Iron is rarely found uncombined in nature except in meteorites, and it rusts readily in moist air. Limonite and hematite are the chief iron ores; other ores include magnetite, taconite, and siderite. Iron ores are refined in a blast furnace to produce pig iron, which can be remelted and poured into molds to make cast iron, commercially purified to make wrought iron, or alloyed with carbon and other elements to make <l:4,45>steel<e>. Iron compounds are used as paint pigments, in dyeing, and in ink manufacture. A component of hemoglobin, the oxygen-carrying pigment of red blood cells in vertebrates, iron is important in nutrition; one cause of anemia is iron deficiency.
