The pure metal is soft, malleable, and has a bright, silvery luster. The metal is fairly stable in air and does not oxidize as rapidly as some of the other rare-earth metals. Erbium oxide is a rose-red compound that is slowly soluble in many mineral acids. It forms a series of rose-colored salts and its solutions have a sweet, astringent taste. Erbium is used in experimental optical amplifiers that amplify light signals sent along fiber-optic cables.
Erbium oxide is used to color glass and porcelain enamel glazes.
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