a|lu|mi|na

a|lu|mi|na «uh LOO muh nuh», noun.

a mineral occurring in nature as corundum, found mainly in bauxite and in clay or loam; aluminum oxide. Emery, rubies, and sapphires are crystalline forms of alumina colored by various impurities. Alumina is used in making aluminum, porcelain, and abrasives. Formula: Al₂O₃

╂[< New Latin alumina < Latin alūmen, -inis alum]