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There are three categories of error coins as provided by the American Numismatic Association. Metal usage and striking errors referred to widely as “planchet errors”, die errors, and mint striking errors. This does not include the varieties that the US Mint has issued over the years.
Since the inception of coin collecting there has been much controversy over what constitutes a true mint error. An organization of coin collectors named the Combined Organizations of Numismatic Error Collectors of America (CONECA) was created that specifically deals with mint errors.
A planchet is produced by punching blanks in sheet metal stock specially made for the types of mint blanks required. After the blanks are punched they are rolled on the edge placing an upset needed for the minting process. The blanks are then washed and annealed making them ready for the minting process
There are several types of planchet errors that include: improper alloy, wrong stock, imperfect blank, and lamination.
A planchet error may be caused by an improper alloy mixture. Improper alloy mixtures occur when the sheet stock contains uneven layers of the metals intended for the type of coin that is produced. A result of improper layers of metals is a coin produced without an intended surface layer of nickel. A dime or quarter without the nickel layer will contain only the copper alloy mixture.
A planchet error can be caused by using a blank intended for a different denomination or wrong stock. The result of using a blank intended for another denomination is the minting of the intended obverse and reverse on the wrong stock.
A planchet error also refers to many types of issues where an imperfect blank has been used. Pieces of the blank might be missing causing a half moon to be missing from the coin. Collectors denote missing parts of the planchet as "clipped planchets." A dirty or oily blank may cause the details of the coin to become dull or even missing. A piece of debris may find its way into the dies causing a series of lines to be minted on the surface of the coin.
A planchet may be in a state that causes peeling on the surface of the coin. The peeling of any part of the surface of a coin is known as a lamination error.
Below is a lamination error on a Jefferson nickel.
Die errors are caused by the mint dies wearing down over time or dies that have not been prepared identical to others that have been replaced. The result of preparing a set of new dies improperly from the original hub results in coin errors such as doubling, extra details, or missing details on the surface of the coin.
A die break is caused when the mint die suffers a crack and this crack feature is transposed onto the coins in the minting process. Coins minted with a die break have a thin line or lines that are raised running across the surface of the coin. Below is a photograph of a 1954-S Jefferson nickel with a die crack along the top of the portrait of Jefferson.
A die break can create coins that have deep impressions in a coin that is filled in with metal. The coin shows a raised patch of metal were the brake occurred. This type of error is commonly known as a "cud" error. Gouges in coins caused by flaws in dies, and die polishing mistakes resulting in coins minted with surface indentations, or polishing lines.
Dies that are damaged and used in the minting process also create errors resulting in coins having die chips embedded in the surface of the coin.
A die clash occurs when a planchet is not fed into the collar that holds the coin in place for the minting process. The two dies meet and each carries away part of the design embedded on the die. Coins minted using these dies cause coins to be minted with parts of the reverse design on the obverse or parts of the obverse on the reverse of the coin. Die rotations cause coins to be minted with the reverse or obverse of the coin partially or fully rotated. A die rotation occurs when the dies become loose and they then turn.
When a mint worker polishes a die to remove a die clash or some other defect there may be instances where a part of the design is removed. The 3-legged Buffalo nickel was the direct result of die polishing and the removal of a leg. The 1970 Lincoln cent with the raised 7 is also the result of die polishing.
Before 1990, all US coin dies were subject to mint mark errors resulting from the preparation of the dies. The mint mark was hammered into the die manually sometimes causing a die to have a doubling. In the minting process this would create a series of coins with a distinct of slight doubling of the mint mark. Millions of these errors can be located on the internet for sale and are referred to as RPM’s
A mint mark is a letter, symbol or an inscription on a coin indicating the mint where the coin was produced.
Double die coins are mainly created by a defective hub which is used to create many dies for the minting process. Collectors classify double dies as DDO (Double die obverse coins), DDR (Double die reverse) and OMM (Over mint mark).
The over mint mark is created when a one date and mint mark is punched over another date, part of a date, or mint mark. These coins are generally restricted to the early minting process of coins dating before the turn of the century.
The DDO and DDR errors are related to any part of the coin that shows a distinct doubling. Pictured below is a 1969-S double die Lincoln cent.
Collectors and organizations dedicated to collecting coins regard mint striking errors as those that have been created by the minting process. Mint striking errors are caused by the collar moving, cracking, or not being present in the minting process. The collar is a third die that actually holds the coin in place in the minting process. It is the collar that imprints the lettering on a coin, such as the lettering on the Presidential dollars.
Striking a coin with debris causes an indentation on the coin or the actual debris stamped into the coin.
In order to mint any US coin a retaining collar is used to keep the coin in place while it is pressed between the dies. If the retaining collar breaks or is missing, the coin is struck so that the metal of the planchet is actually expanded outward producing a larger version of the coin with most of the details present. This error is known as a broad struck error.
A coin that has been struck out of the collar and has double details such as two partial portraits, one normal and one that is overlapping and extending outside the normal circumference of the coin is denoted as a double striking error.
A brockage results when a coin is stuck in the collar and another planchet enters the collar and is pressed against the coin already minted. The details of the coins produced have the appearance of mirror images of the obverse and reverse.
A die cap is a coin that has been stamped a number of times and has the appearance of a soda cap. Metal flows around the side of the coin and the portrait appears deep in the coin.
Variations are not mint errors in the technical sense.
Variations in coins are caused by creating hubs and dies that are not exactly the same resulting in dates that can be compared as large to small, wide to thin etc. These die variations resulted in the 1960 large- and small-dated Lincoln cent, and the 1982 large- and small-dated series both in copper and copper-zinc cents minted.
The Lincoln cent is a one-cent coin that has been struck by the United States Mint since 1909. The obverse or heads side was designed by Victor David Brenner, as was the original reverse, depicting two stalks of wheat. The coin has seen several reverse, or tails, designs and now bears one by Lyndall Bass depicting a Union shield. All coins struck by the United States government with a value of 1/100 of a dollar are called cents because the United States has always minted coins using decimals. The penny nickname is a carryover from the coins struck in England, which went to decimals for coins in 1971.
Below are photographs of two Brilliant Uncirculated Jefferson nickels. Note that these are variations of dies used to mint the 1970-D Jefferson nickels. The die variation is clearly evident with the placement of the D in two different locations, one closest to the 1970 and the other closest to the rim of the coin.
There are some variations created by the mint site using different die sets. The best case of the mint using different die sets is the variation of the letters AM on the Lincoln cent. The AM letters are either touching or are distinctly apart in some Lincoln cents minted in 1998, 1999, 2000, and perhaps others to be discovered. Normally, the wide AM design is reserved for the Lincoln proof designs. Below is a photograph of a wide AM Lincoln cent.
Unclassified error coins are those that are difficult to categorize. Below are two unclassified error, one with the date flattened in a 1998 Jefferson nickel and another Jefferson nickel with a recessed S.
Counter stamped coins have a long history in the early days of minted coins. Many companies used counter stamping as a method to advertise their company. There are thousands of counter stamped coins some of which carry little value while others command values in the thousands. In any case, these coins were changed after leaving the mint, and are not true error coins.
Initials were sometime cut into coins. Some of these coins have been classified as "love tokens" having the initials of the person who counter stamped the coin. Below is a counter stamped Lincoln cent with a number 2 in a bar shape outline. This coin was found with some others with personal initials in a 5,000 piece coin bag purchased from a coin show.
The United States one-cent coin, often called the penny, is a unit of currency equaling one one-hundredth of a United States dollar. It has been the lowest-value physical unit of U.S. currency since the abolition of the half-cent in 1857. The first U.S. cent was produced in 1787, and the cent has been issued primarily as a copper or copper-plated coin throughout its history. Its obverse has featured the profile of President Abraham Lincoln since 1909, the centennial of his birth. From 1959 to 2008, the reverse featured the Lincoln Memorial. Four different reverse designs in 2009 honored Lincoln's 200th birthday and a new, "permanent" reverse – the Union Shield – was introduced in 2010. The coin is 0.75 inches (19.05 mm) in diameter and 0.0598 inches (1.52 mm) in thickness. Its weight has varied, depending upon the composition of metals used in its production.
1943 steel cents are U.S. one-cent coins that were struck in steel due to wartime shortages of copper. The Philadelphia, Denver, and San Francisco mints each produced these 1943 Lincoln cents. The unique composition of the coin has led to various nicknames, such as wartime cent, steel war penny, and steelie. The 1943 steel cent features the same Victor David Brenner design for the Lincoln cent which had been in use since the first in 1909.
Mint-made errors are errors in a coin made by the mint during the minting process. Groups of coins with distinctive characteristics are known as varieties. The term variety applies to coins with both intended and unintended differences while the term error refers only to coins with unintended differences. Nevertheless, not all errors are varieties. Although there may be many identical examples of a some errors, others are unique. For example, there may be many indistinguishable examples of coins with a specific die crack, while off-center strikes tend to be unique. Being unique does not mean that an error is valuable. Although no other coin may be similar to a coin with an off-center strike, off-center strikes happen often enough that buyers can choose from many examples each of which varies slightly from the other.
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.
A nickel, in American usage, is a five-cent coin struck by the United States Mint. Composed of 75% copper and 25% nickel, the piece has been issued since 1866. Its diameter is .835 inches (21.21 mm) and its thickness is .077 inches (1.95 mm). Due to inflation, the purchasing power of the nickel continues to drop and currently the coin represents less than 1% of the federal hourly minimum wage. In 2015, over 1.5 billion nickels were produced at the Philadelphia and Denver mints.
A planchet is a round metal disk that is ready to be struck as a coin. An older word for planchet is flan. They are also referred to as blanks.
A mint is an industrial facility which manufactures coins that can be used as currency.
The 1955 doubled die cent is a die variety that occurred during production of the one cent coin at the United States Mint in 1955.
Doubled die is a term in numismatics used to refer to doubling in the design elements of a coin. Doubled dies can appear as an outline of the design or in extreme cases, having legends and dates appear twice in an overlapping fashion.
In numismatics, a mule is a coin or medal minted with obverse and reverse designs not normally seen on the same piece. These can be intentional or produced by error. This type of error is highly sought after by collectors, and examples can fetch high prices.
The Indian Head cent, also known as an Indian Head penny, was a one-cent coin ($0.01) produced by the United States Bureau of the Mint from 1859 to 1909. It was designed by James Barton Longacre, the Chief Engraver at the Philadelphia Mint.
In coin collecting, a key date refers to a date of a given coin series or set that is harder to obtain than other dates in the series. The next level of difficult to obtain coins in series are often referred to as semi-key dates or simply semi-keys.
The United States large cent was a coin with a face value of 1/100 of a United States dollar. Its nominal diameter was 11⁄8 inch (28.57 mm). The first official mintage of the large cent was in 1793, and its production continued until 1857, when it was officially replaced by the modern-size one-cent coin.
This article is a collection of Numismatic and coin collecting terms with concise explanation for the beginner or professional.
The Shield nickel was the first United States five-cent piece to be made out of copper-nickel, the same alloy of which American nickels are struck today. Designed by James B. Longacre, the coin was issued from 1866 until 1883, when it was replaced by the Liberty Head nickel. The coin takes its name from the motif on its obverse, and was the first five-cent coin referred to as a "nickel"—silver pieces of that denomination had been known as half dimes.
The silver center cent is an American pattern coin, one of the precursors to the large cent and an early example of a bimetallic coin. Less than a dozen specimens are known to exist today, and they generally fetch substantial prices; an uncirculated silver center cent sold at auction for $414,000 in January 2002. That price was eclipsed by an example graded PCGS MS61 offered at auction in April 2012, with a price tag of more than $1 million.
The Jefferson nickel has been the five-cent coin struck by the United States Mint since 1938, when it replaced the Buffalo nickel. From 1938 until 2004, the copper-nickel coin's obverse featured a profile depiction of founding father and third U.S. President Thomas Jefferson by artist Felix Schlag; the obverse design used in 2005 was also in profile, though by Joe Fitzgerald. Since 2006 Jefferson's portrayal, newly designed by Jamie Franki, faces forward. The coin's reverse is still the Schlag original, although in 2004 and 2005 the piece bore commemorative designs.
In minting, coining or coinage is the process of manufacturing coins using a kind of stamping which is now generically known in metalworking as "coining". This process is different from cast coinage, and can be classified in hammered coinage or hammering and milled coinage or milling.
The Castaing machine is a device used to add lettering and decoration to the edge of a coin. Such lettering was necessitated by counterfeiting and edge clipping, which was a common problem resulting from the uneven and irregular hammered coinage. When Aubin Olivier introduced milled coinage to France, he also developed a method of marking the edges with lettering which would make it possible to detect if metal had been shaved from the edge. This method involved using a collar, into which the metal flowed from the pressure of the press. This technique was slower and more costly than later methods. France abandoned milled coinage in favour of hammering in 1585.