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Mint-made errors are errors in a coin made by the mint during the minting process. They are almost always accidental and usually very rare, making them valuable to numismatists. Authentic error coins must not be confused with coins that have incurred damage after being minted.

Contents 1 Planchet errors 2 Hub and die errors 3 Strike errors 4 Famous U.S. coin varieties and errors 5 RPMs 6 PUP 7 See also

Planchet errors occur when the wrong coin blanks, or planchets, are fed into a coin-stamping press. This results in a coin that has been stamped with a design intended for a differently sized coin; this is called a wrong planchet error. In addition, unminted or blank planchets are occasionally produced. The results are usually obvious errors that are also prized by collectors, though the errors are usually caught in manufacturing and destroyed. Blank planchets with rims are valued lower than those with no rim.

A Kennedy half dollar struck on a Susan B. Anthony planchet is extremely rare. Sacagawea dollars exist with a state quarter design on the back; this type of error is called a mule, and unintentional ones are rare.

Hub and die errors are the result of faults in the coin hub or coin die. There are many different kinds of such errors. Modern coins are still released with hub and die errors, because the defects are too small to be seen with the naked eye. A few exceptions exist, where the dies are used despite producing easily visible flaws. The 1955 Lincoln cent is an example.

Strike errors occur when the planchet is struck. It is a fault in the manufacturing process rather than in either the die or the planchet. A standard type of strike error is a broadstrike, where the rim image is not struck into the coin's edge because the collar die was missing. Numismatists often prize strike error coins over perfectly struck examples, which tend to be more common, but less highly than die error coins, which are usually rarer, making it valuable.

• 1937-D 3-leg Indian Head nickel
• 1943 bronze cent
• 1955 Lincoln cent
• 1978 quarter with dot mint mark
• 1982 No P dime
• 2001-P doubled-die New York quarter
• 2004 cracked die Texas quarter
• 2004 three leaf Wisconsin quarter
• 2007 Godless dollar

RPM stands for repunched mint marks. It occurs when the mint mark on a coin is struck twice, overlapping the previous mark.

PUP stands for "pick-up point". It refers to the affected area of an error coin where the error occurs. For example, if you had a double die (DDO) kennedy half dollar and there was doubling in the L and R of liberty the pickup point (PUP) would be on the L and R of "LIBERTY" on the coin.

• Coin die
• Doubled die
• Die deterioration doubling