A trivalent element, pure erbium metal is malleable, soft yet stable in air and does not oxidize as quickly as some other rare-earth metals. Its salts are rose-colored and the element gives a characteristic sharp absorption spectra in visible light, ultraviolet, and near infrared. Otherwise it looks much like the other rare earths. Its sesquioxide is called erbia. Erbium's properties are to a degree dictated by the kind and amount of impurities present. Erbium does not play any known biological role but is thought by some to be able to stimulate metabolism.
Erbium's everyday uses are varied. It is commonly used as a photographic filter and because of its resilience it is useful as an metallurgical additive.
Other uses include
- Neutron absorber in nuclear technology.
- Dopant in fiber optic laser amplifiers.
- When added to vanadium as an alloy erbium lowers hardness and improves workability.
- Erbium oxide has a pink color and is therefore sometimes used as a glass and porcelain enamel glaze colorant. The glass is then often used in sunglasses and cheap jewelry.