Which rock is the world’s main source of aluminum?

Bauxite is the world’s main source of aluminum.

Bauxite is a deeply weathered rock enriched in aluminum hydroxide minerals, especially gibbsite, boehmite, and diaspore. It commonly forms in tropical and subtropical regions where intense rainfall removes many soluble elements from the parent rock while aluminum remains concentrated.

To produce aluminum, refineries first process bauxite into alumina, or aluminum oxide, using the Bayer process. Smelters then use the Hall–Héroult process to reduce alumina to metallic aluminum. Bauxite is therefore an ore rather than a single mineral, a distinction that is often missed in short descriptions.

Major bauxite deposits occur in Australia, Guinea, Brazil, China, and India. The red or brown color of many deposits comes mainly from iron oxides mixed into the weathered material.