Iron ore is one of the three naturally magnetic elements; the others are cobalt and nickel. It is one of the three naturally magnetic elements; the others are cobalt and nickel. Iron ore is one of the three naturally magnetic elements; the others are cobalt and nickel. About 98% of iron ore is used to make steel - one of the greatest inventions and most useful materials ever created. Currently most of the iron ore mined in the world comes from large deposits of massive hematite rock formed by the in situ enrichment of a protore already enriched in iron, most commonly a banded iron formation. It is estimated that worldwide there are 800 billion tons of iron ore resources, containing more than 230 billion tons of iron. It is also estimated that the United States has 110 billion tons of iron ore representing 27 billion tons of iron. Among the largest iron ore producing nations are Russia, Brazil, China, Australia, India and the USA.