The grey-white metal called platinum is malleable, ductile, and extremely dense. The metal was discovered in South America during the first half of the 18th century. Platinum-bearing igneous rocks give rise to the associated placer deposits, the most productive sources of the native element.
Platinum is one of the noble metals, so called because it is chemically non-reactive.
In the United States the largest consumers of the metal are the chemical and electrical industries. Platinum catalysts are used in the commercial production of sulphuric and nitric acids as well as in the catalytic cracking process for refining petroleum. Durable electrical contacts made of platinum are utilised in the switches of communication systems because the metal resists the high temperatures and corrosion of electric arcs. Platinum has proved its versatility in other areas as well. The alloy of platinum and iridium is highly heat resistant and is used for melting pots and moulds in the preparation of lasers.