Base metals include Copper, Aluminum, Zinc, Lead, Nickel and Tin.
Compared to the precious metals, Gold, Silver, Platinum and Palladium, base metals are less malleable and more chemically reactive. They are also more abundant than precious metals. They are widely used in commercial and industrial applications.
Base metals corrode and oxidize when when exposed to air and water. With the exception of copper, they all react with hydrochloric acid to form hydrogen.
Contracts for copper, lead, nickel and zinc are traded on the London Metal Exchange.