Zinc, a bluish-white, lustrous, metallic element. Zinc is one of the most widely used of all metals in industry. When metallic zinc is exposed to moist air, its surface changes into basic zinc carbonate, which protects the underlying zinc from further chemical reactions. For this reason, zinc is often used to coat iron or steel to protect them from corrosion. Metals thus treated are said to be galvanized. Zinc is used in making brass, nickel silver, and die-casting alloys. It is also used to make the negative electrodes in several types of electric batteries. United States pennies issued after 1981 are composed largely of zinc.