Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Die deterioration doubling (DDD) is an extremely common form of mint-made error on many United States and Canadian coins that results from degradation of the die used to strike the coin. Due to a combination of improper preparation and treatment of the dies, excessive wear, and overuse, die deterioration doubling has occurred on nearly every series issued by the US mint in recent times. Certain coins are more susceptible to it than others, due to various factors, but it does occur on most series of coins.

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