Germanium is a metalloid element that has interesting properties useful in electronic applications. It was discovered in 1886 by Clemens Winkler, who named it after his homeland of Germany. Germanium is extracted mainly from sphalerite, a mineral that contains zinc sulfide. The chemical and physical properties of germanium make it useful in electronic applications such as transistors, diodes, and infrared light detectors. Germanium is also used to make precision lenses for infrared spectroscopy applications. While germanium is not an essential element for living organisms, it may have some therapeutic applications in medicine.