Collectible Mint Error Coins.

Mint Error Coin: Double Striking Error

Mint Error Coin: Broadstriking Error

Mint error coins are hugely collectible - although mints routinely screen their coins for mis-struck ones, some rare ones managed to escape into general circulation and became very collectible.

Studium Magazine has a neat list of various types of mint error coins, including clipped planchet, off-center striking, double striking, and broadstrike.

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