Beryllium is a silvery-white metal. It is relatively soft and has a low density.Beryllium is used in alloys with copper or nickel to make gyroscopes, springs, electrical contacts, spot-welding electrodes and non-sparking tools. Mixing beryllium with these metals increases their electrical and thermal conductivity.Other beryllium alloys are used as structural materials for high-speed aircraft, missiles, spacecraft and communication satellites.Beryllium is relatively transparent to X-rays so ultra-thin beryllium foil is finding use in X-ray lithography. Beryllium is also used in nuclear reactors as a reflector or moderator of neutrons.The oxide has a very high melting point making it useful in nuclear work as well as having ceramic applications.