Erbium takes its name from Ytterby, the Swedish village from which a remarkable number of rare earth elements were first identified.

It was discovered in 1843 by Swedish chemist Carl Gustaf Mosander, who separated it from a sample of yttria.

Erbium has atomic number 68 and the chemical symbol Er. It is a lanthanide and a rare earth element: a soft, silvery-white metal that is relatively stable in air at room temperature. Its melting point is 1,529 degrees Celsius and its boiling point is 2,868 degrees Celsius.

Its most commercially important application is in fiber optic amplifiers. Erbium-doped fiber amplifiers, commonly referred to as EDFAs, boost optical signals as they travel through long-distance telecommunications cables, making them essential infrastructure for modern global communications.

Erbium also appears in lasers, particularly erbium-doped yttrium aluminum garnet lasers, used in dermatology for skin resurfacing and in dentistry for procedures such as cavity preparation.

Erbium compounds give glass and ceramics a distinctive pink or rose coloration. Erbium-doped glass is used in decorative art glass and in some sunglasses. The element also serves as a neutron absorber in nuclear control rods. Like other rare earth elements, it has no known biological function and is considered to have low toxicity.