Iridium is a transition metal that is a bright silver white color in its natural solid state. It can be attached by molten salts, but it has the strongest anti-corrosive properties of all the metal elements. Iridium has an atomic weight of 192.217, a melting point of 4471 °F, and a boiling point of 8002 °F. Some common uses of iridium include: as a component in platinum alloys as a hardening agent, as a component in crucibles that must withstand high temperatures, as a component in spark plugs, and in radiation therapy.