Alumina

Alumina, also called aluminum oxide, synthetically produced aluminum Oxide, Al_2O3, a white or nearly colorless crystalline substance that is used as a starting material for the Smelting of aluminum metal. It also serves as the raw material for a broad range of advanced ceramic products and as an active agent in chemical processing.

Alumina is made from bauxite, a naturally occurring ore containing variable amounts of hydrous (water-containing) aluminum oxides. Free Al₂O₃ occurs in nature as the mineral corundum and its gemstone forms, sapphire  and ruby; these can be produced synthetically from alumina and in fact are occasionally referred to as alumina, but the term is more properly limited to the material employed in aluminum metallurgy, industrial ceramics, and chemical processing.

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