Why is aluminium the most abundant metal in the crust

Aluminium is the most abundant metal in Earth’s crust (about 8%) because it strongly bonds with oxygen to form stable minerals like feldspars, clays, and bauxites, which resist weathering and accumulate widely in crustal rocks.

Geological explanation

• Chemical affinity: Aluminium readily forms Al³⁺, which bonds strongly with oxygen to produce aluminosilicates.
• Stable minerals: Feldspars and aluminosilicates dominate igneous rocks, the most common crustal rocks.
• Crustal processes: During partial melting and differentiation, aluminium tends to stay in the crust rather than sink into the core.
• Resistance to removal: Aluminium-rich minerals resist dissolution, so they persist in soils and sediments.

Key fact

Although aluminium is abundant in the crust, it is almost absent in the native metallic form. Extraction requires processing alumina (Al₂O₃) from bauxite.