Unusual Coins

The triangular coin (produced to commemorate the 2007/2008 Tutankhamun exhibition at The O2 Arena) was commissioned by the Isle of Man, became legal tender on 6 December 2007. crown). Other triangular coins issued earlier include: Cabinda coin, Bermuda coin, 2 Dollar Cook Islands 1992 triangular coin, Uganda Millennium Coin and Polish Sterling-Silver 10-Zloty Coin.
Guitar-shaped coins were once issued in Somalia. Poland once issued a fan-shaped 10 złoty coin and the 2002 $10 coin from Nauru, was Europe-shaped.
Some mediaeval coins, called bracteates, were so thin they were struck on only one side.
The Royal Canadian Mint is now able to produce holographic-effect gold and silver coinage. However this procedure is not limited to only bullion or commemorative coinage. The 500 yen coin from Japan, was subject to a massive amount of counterfeiting. The Japanese government in response produced a circulatory coin with a holographic image.