Erbium is a chemical element in the lanthanide series, with symbol Er and atomic number 68. As a silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements on Earth.
Erbium's principal uses involve its pink-colored Er3+ ions, which have optical fluorescent properties particularly useful in certain laser applications. Erbium-doped glasses or crystals can be used as optical amplification media. This process results in an unusually mechanically simple laser optical amplifier for signals transmitted by fiber optics.
In addition to optical fiber amplifier-lasers, a large variety of medical applications (i.e. dermatology, dentistry) utilize the erbium ion, which is highly absorbed in water in tissues, making its effect very superficial. Such shallow tissue deposition of laser energy is helpful in laser surgery, and for the efficient production of steam which produces enamel ablation by common types of dental laser.