Explanation:

- Mica is a group of silicate minerals known for their sheet-like formation and used in electrical and thermal insulation, not aluminum smelting.

- Gypsum is a soft sulfate mineral used primarily in building materials like drywall, not for producing aluminum.

- Bauxite is the correct answer. It's a reddish-brown ore, rich in aluminum oxide, used as the primary raw material in aluminum production.

- Conglomerate is a sedimentary rock composed of rounded fragments, not related to aluminum production.