With some 8 % aluminium is the third most abundant element of the earth's crust; iron follows with some 6 %. Aluminium never occurs in pure form but – due to its high reactivity – is always combined with oxygen.
The best-known aluminium mineral is bauxite that can be open-cast mined. It is named after the French village Les Baux where the ore was first mined. Bauxite is sedimentary rock mainly from the components aluminium oxide (40- 60 %), ferrous oxide (5 – 30 %) and silica (5 – 30 %). The predominantly red colour of bauxite is due to the presence of ferrous oxides. The richest deposits of bauxite are found in Brazil, China, Australia, Guinea, West Africa and India. Based on the current rate of consumption the reserves will last for another 400 years.