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Mint-made errors
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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 in modern minting are usually very rare, making them valuable to numismatists. Minting errors are far more common in older coinage, understandably. Authentic error coins must not be confused with coins that have incurred damage after being minted.
chet errors occur when the wrong coin blanks, or planchets, are fed into a coin-stamping press.
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Encyclopedia
Mint-made errors are errors in a coin made by the mint during the minting process. They are almost always accidental and in modern minting are usually very rare, making them valuable to numismatists. Minting errors are far more common in older coinage, understandably. Authentic error coins must not be confused with coins that have incurred damage after being minted.
Types
Planchet errors
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.
Occasionally a misfeed can occur where a strip isn't fed through far enough. When this happens, the punches strike an area of the strip which overlaps the hole left by the previous strike. The result is a blank with a piece missing.
A clipped planchet is straight, curved, ragged, incomplete, or elliptical.
A wrong planchet occurs when a denomination is struck on a planchet of a different denomination. Some examples include cents struck on dime planchets, nickels on cent planchets, or quarters on dime planchets. Sacagawea dollars have been reported with statehood quarter designs on the reverse. A much rarer error is a U.S denomination struck on a foreign planchet (17th,18th, and 19th centuries only).
Hub and die errors
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
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.
Broadstrike errors are produced when the collar die malfunctions. The collar is the circular die surrounding the anvil (lower) die. It applies the edge device (reeded edge, plain edge) and prevents the metal of the coin being struck from flowing outside of the confines of the die. When the collar is prevented from working properly during striking, it may rest below the surface of the anvil die. All denominations of U.S. coins with a broadstrike have a plain edge.
Overdate
In the past, it was a common practice for a mint to use a certain die until it broke. As some dies would last for multiple years, a figure would be punched over the old date. For example, some 1942 Mercury dimes show a 1 beneath the 2.
Numismatic value of error coins
Most error coins demand a premium when sold, if they are modern coins, dependent upon the rarity of the type of error as well as the rarity of that type of error on a particular denomination. The value of error coins has been subject to much debate and the value is usually determined between the dealer and the collector. Conversely, errors on ancient, medieval and higher value coins are usually detrimental to the coins numismatic value.
Defective die
A coin shows a raised line on its surface. This is caused by a crack in the die used to strike the planchet. Coins sometimes show an unstruck area resulting from a break in the die. This is known as a cud mark. In U.S. coinage, many coins from the Morgan Dollar series show slight die cracks.
Lamination
A coinage defect consisting of a portion of the metal separating from the rest due to impurities or internal stresses. Lamination flaws occur primarily when a foreign material or gas oxide becomes trapped within the planchet (the metal blank used as a coin). This error is especially common to the modern US Cent having a zinc metal base plated with a thin sheeting of copper.
Brockage
A mirror image of a coin has been struck on both sides of the planchet. This error typically occurs when a coin remains on either die after striking. The second coin receives the image from the die, though its blank other side also receives the image of the struck coin. The result is an incuse mirror image, and the coin is known as a brockage error.
Multiple strike
This occurs when the coin has an additional image on one side from being struck again, off center. The result is sometimes mistaken as being a "doubled die". Note: Also referred to as 'double exposure.'
Famous U.S. coin varieties and errors
Terms
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.
See also
External links
- - An interactive forum with pictures of error coins and detailed explanation of how these errors occur.
- - Pictures of error coins and detailed explanation of how these errors occur on various coins.
- - Free information about British coins. Includes an online forum and a section on error coins.
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