Copper-nickel (also known as cupronickel) is an alloy of copper and nickel, most commonly about 75% copper and 25% nickel for coinage. It has a silvery-grey appearance and offers good corrosion and wear resistance, making it well suited to circulation coins. Copper-nickel became widespread for low- and mid-denomination coinage from the second half of the 19th century when precious metals were progressively withdrawn from everyday use, and it remains one of the most common materials used for circulation coins worldwide today.
