What is aluminum?

It is a strong metallic rust proof metal.
Aluminium is a silvery white and ductile member of the boron group of chemical elements. It has the symbol Al; its atomic number is 13. It is not soluble in water under normal circumstances. Aluminium is too reactive chemically to occur in nature as the free metal. Instead, it is found combined in over 270 different minerals.
The chief source of aluminum is bauxite ore.
Aluminium is a soft, durable, lightweight, malleable metal with appearance ranging from silvery to dull grey, depending on the surface roughness. Aluminium is nonmagnetic and nonsparking. It is also insoluble in alcohol, though it can be soluble in water in certain forms. The yield strength of pure aluminum is 7-11 MPa, while aluminum alloys have yield strengths ranging from 200 MPa to 600 MPa. Aluminium has about one-third the density and stiffness of steel. It is ductile, and easily machined, cast, and extruded.
Aluminium is a good thermal and electrical conductor, by weight better than copper. Aluminium is capable of being a superconductor, with a superconducting critical temperature of 1.2 kelvin and a critical magnetic field of about 100 gauss.
However, because of its strong affinity to oxygen, it is almost never found in the elemental state; instead it is found in oxides or silicates. Feldspars, the most common group of minerals in the earth's crust, are aluminosilicates. Native aluminum metal can be found as a minor phase in low oxygen fugacity environments, such as the interiors of certain volcanoes.
Although aluminum is an extremely common and widespread element, the common aluminum minerals are not economic sources of the metal. Almost all metallic aluminum is produced from the ore bauxite. Bauxite occurs as a weathering product of low iron and silica bedrock in tropical climatic conditions.