Bauxite is also called bauxite or bauxite. Its main component is aluminum oxide, which is hydrated alumina containing impurities. It is an earthy mineral. White or off-white, brown or light red due to iron content. The density is 3.9~4g/cm3 and the hardness is 1~3. It is opaque, brittle, extremely difficult to melt, insoluble in water, and soluble in sulfuric acid and sodium hydroxide solutions. Mainly used for smelting aluminum and making refractory materials.