There are seven different types of Mint error coins that you may encounter when collecting coins. The key here is that all the errors originate with the Mint. These error coins generally do not circulate very long before being noticed, so most of the time your will encounter them in near new to uncirculated condition. Below are the textbook definitions according the the Guide Book Of United States Coins.
- Clipped Planchet – an incomplete coin missing 10 to 25% of the metal.
- Multiple Strikes – a coin with at least one additional image from being struck again off center
- Blank Planchet – a blank disc of metal intended for coinage but not struck with dies.
- Defective Die – a coin showing raised metal from a large die crack, or small rim break.
- Off Cents – a coin that has been struck out of collar and incorrectly centered with part of the design missing.
- Broadstrike – a coin that was stuck outside the retaining collar.
- Lamination – a flaw whereby a fragment of metal has peeled off the coins surface.
- Brockage – a mirror image of the design.
It can be difficult for the amateur or even a seasoned coin collector to discern error coins from a normal coin with the typical wear and tear that a circulating coin receives. So it is best to show it to a reputable rare coin dealer to be sure. Values are lower for modern coins and higher when encountered in the older series.