<P> Iron ores are rocks and minerals from which metallic iron can be economically extracted . The ores are usually rich in iron oxides and vary in colour from dark grey, bright yellow, or deep purple to rusty red . The iron itself is usually found in the form of magnetite (Fe 3O 4, 72.4% Fe), hematite (Fe 2O 3, 69.9% Fe), goethite (FeO (OH), 62.9% Fe), limonite (FeO (OH) n (H O), 55% Fe) or siderite (FeCO, 48.2% Fe). </P> <P> Ores containing very high quantities of hematite or magnetite (greater than about 60% iron) are known as "natural ore" or "direct shipping ore", meaning they can be fed directly into iron - making blast furnaces . Iron ore is the raw material used to make pig iron, which is one of the main raw materials to make steel--98% of the mined iron ore is used to make steel . Indeed, it has been argued that iron ore is "more integral to the global economy than any other commodity, except perhaps oil". </P>

Where does iron come from in the world