Most metals that we use come from metal ores found in the earth's crust. Metal ores are made up of different compounds. Bauxite for example contains about 99 percent aluminum and magnetite about 72 percent iron. These metal ore deposits that contain large percentages of a single element are the easiest to extract. Some deposits contain less, but the cost to extract lower amounts of a specific metal is high. Some common types of metals common to ores include copper, gold and silver, aluminum, iron and nickel.
Copper is a mineral that was used thousands of years ago by ancient civilizations, and is still being used today. Copper can be extracted cheaply and its properties and uses make it valuable as a commodity. Copper ore can be found close to the earth's surface, as well as in deep-sea pockets. It is believed that underwater volcanic activity can produce nodules of copper, magnesium and other metals. Copper is mined in the western part of the United States, Australia, Canada, Mexico, China and a few other countries.
Most aluminum comes from the rock bauxite which is a mixture of hydrated aluminum oxides. It is considered a rock because bauxite is made of multiple minerals, like gibbsite, diaspore and boehmite. Australia produces over 40 percent of the world's aluminum ore. Countries like Brazil, Guniea and Jamaica are also important producers. The United States does not produce much bauxite but it does import and refine a large number of alumina, an aluminum oxide, and aluminum, the processed metal.
Gold and Silver
Gold and silver have been used as currency but have other uses as well. Gold has been used in dentistry and medicine, scientific equipment and as an electrolyte in electroplating. Silver has also been used in dentistry, as a conductive material, and as a photographic material. Most gold comes from South Africa, making up almost half of the world's resources, but can also be found in the United States, Australia, Brazil and Russia. Silver can be found in other ore deposits, like lead, zinc, gold and copper. The United States, Mexico, Chile and Canada are also important producers.
Iron makes up about 5 percent of the Earth's crust. It is one of the three most magnetic materials and comes mainly from magnetite, containing 72 percent iron, and hematite, containing 70 percent iron. Hematite deposits can be found in banded iron formations, which are alternating layers of many types of mineral quarts, as well as iron rich ores. These bands are believed to have been formed during the Proterozoic Eon of the Earth's natural history.
Nickel is a malleable metal that is also one of the three magnetic metals and is also conductive. Of the nickel available for extraction, 60 percent is contained in laterite deposits. Laterite deposits are concentrations of nickel and nickel-rich rock that are pulled up to the Earth's surface by rain and water.
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