Claim: Aluminium is used by rocket scientists.

Aluminium or aluminum -LRB- see below -RRB- is a chemical element in the boron group with symbol Al and atomic number 13 . It is a silvery-white , soft , nonmagnetic , ductile metal . By mass , aluminium makes up about 8 % of the Earth 's crust ; it is the third most abundant element after oxygen and silicon and the most abundant metal in the crust , though it is less common in the mantle below . Aluminium metal is so chemically reactive that native specimens are rare and limited to extreme reducing environments . Instead , it is found combined in over 270 different minerals . The chief ore of aluminium is bauxite .   Aluminium is remarkable for the metal 's low density and its ability to resist corrosion through the phenomenon of passivation . Aluminium and its alloys are vital to the aerospace industry and important in transportation and structures , such as building facades and window frames . The oxides and sulfates are the most useful compounds of aluminium .   Despite its prevalence in the environment , no known form of life uses aluminium salts metabolically , but aluminium is well tolerated by plants and animals . Because of these salts ' abundance , the potential for a biological role for them is of continuing interest , and studies continue .