Erbium is a chemical element with the symbol Er and atomic number 68. It is a soft, silvery-white metal that belongs to the lanthanide series of the periodic table. Erbium is primarily used in various applications, including fiber optics, where it helps amplify signals, and in certain types of lasers. This element is found in nature mainly in minerals such as monazite and xenotime. Erbium is known for its unique properties, including its ability to absorb and emit light in the infrared spectrum, making it valuable in medical and industrial technologies.