Element No. 78 is the chemical element Platinum, which is a transition metal and a member of the platinum group of elements. It is a dense, malleable, ductile, highly unreactive, precious, silverish-white transition metal. Platinum is a rare element, occurring in some nickel and copper ores, as well as in native deposits. It is used in jewelry, laboratory equipment, electrical contacts and electrodes, platinum resistance thermometers, dentistry equipment, and catalytic converters.