Because aluminium metal reacts with water and air to form powdery oxides and hydroxides, aluminium metal is never found in nature. Many common minerals, including feldspars, contain aluminium, but extracting the metal from most minerals is very energy-intensive, and therefore expensive.

The main ore of aluminium is bauxite. Bauxite is the name for a mixture of similar minerals that contain hydrated aluminium oxides. These minerals are gibbsite (Al(OH)3), diaspore (AlO(OH)), and boehmite (AlO(OH)). Because it is a mixture of minerals, bauxite itself is a rock, not a mineral. Bauxite is reddish-brown, white, tan, and tan-yellow. It is dull to earthy in luster and can look like clay or soil. Bauxite forms when silica in aluminium-bearing rocks (that is, rocks with a high content of the mineral feldspar) is washed away (leached). This weathering process occurs in tropical and subtropical weathering climates.

Alternative sources of aluminium might someday include kaolin clay, oil shales, and even coal waste. However, as long as bauxite reserves remain plentiful and production costs are low, the technologies to process these alternative sources into alumina or metallic aluminium will likely not progress beyond the experimental stage.

Australia has huge reserves of bauxite, and produces over 40% of the world’s ore. Brazil, Guinea, and Jamaica are important producers, with lesser production from about 20 other countries. The United States’ production, which was important 100 years ago, is now negligible.

Most bauxite is first processed to make alumina, or aluminium oxide, a white granular material. Sometimes, raw bauxite is shipped overseas for processing to alumina, while in other cases it is processed near the mine. Alumina is lighter than bauxite because the water has been removed, and it flows readily in processing plants, unlike bauxite which has a sticky, muddy consistency. Australia, the United States, and China are the largest producers of alumina. All the U.S. alumina being made is from imported bauxite.

Aluminium metal is refined from alumina, usually in industrialized countries having abundant supplies of cheap hydroelectric power. The refining process is the Hall-Heroult Process, named after Charles Hall of the U.S. and Paul L.T. Heroult of France, who each independently invented the process in 1866. In this process, alumina (aluminium oxide) is dissolved in molten cryolite (cryolite is an aluminium fluoride mineral, Na3AlF6). The alumina is then separated into its elements by electrolysis. Though attempts have been made to replace this process, it is to this day the only method used to isolate aluminium on a commercial scale.

The largest producers of aluminium metal are Russia, China, the United States, and Canada, countries which have abundant hydroelectric power. More than 40 other countries also produce aluminium, including Norway, Iceland, Switzerland, Tajikistan, and New Zealand, which are small but mountainous, and have many rivers to provide hydroelectric power. Other areas of the world with access to abundant and cheap electricity, such as the Middle East, are also expanding their metal production capacities.
Recycling of aluminium by melting cans and other products is an important source of metal in many developed countries.

About 85% of all the bauxite mined worldwide is used to produce alumina for refining into aluminium metal. Another 10% produces alumina which is used in chemical, abrasive, and refractory products. The remaining 5% of bauxite is used to make abrasives, refractory materials, and aluminium compounds.

The lightness, strength, and corrosion resistance of aluminium are important considerations in its application. Metallic aluminium is used in transportation, packaging such as beverage cans, building construction, electrical applications, and other products.

Aluminium, the third most abundant element at the Earth’s surface, is apparently harmless to plant and animal life.