Bi-metallic coins

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The 1 euro coin is bi-metallic: the inner part of cupronickel, the outer part of nickel brass

Bi-metallic coins are coins consisting of more than one metal or alloy, generally arranged with an outer ring around a contrasting center. Common circulating examples include the €1, €2, British £2, Canadian $2 and South African R5.

Bi-metallic coins have been issued for a long time, with examples known dating from the 1600s. The silver-center cent pattern produced by the United States in 1792 is another example. In recent times, the first circulating bi-metallic coin was probably the 500 Italian lire, first issued in 1982. France, with a 10 franc coin and Thailand, with a 10 baht, issued bi-metallic coins for circulation in 1988.

As well as circulating coins, where they are generally restricted to high denomination coins, bi-metallic coins are often used in commemorative issues, they are used as a way of securing against Coin counterfeiting.

The manufacturing process is similar to that of ordinary coins, except that two blanks (the inner and the outer) are struck at the same time, deforming the separate blanks sufficiently to hold them together.