Platinum

Platinum is a dense, silvery-white transition metal that is remarkably resistant to corrosion. It occurs naturally in some nickel and copper ores and in deposits of nearly pure metal, but it is scarce in Earth's crust. Most platinum is obtained as a by-product when nickel and copper ores are processed. Its resistance to heat and chemical attack makes it useful in catalytic converters, which help clean vehicle exhaust, and in laboratory equipment and electrical contacts. Platinum is also prized for durable jewelry. Some platinum compounds—not the metal itself—are used in medicines that treat certain cancers.