Error coins are a unique and fascinating aspect of numismatics that add an extra layer of interest and rarity to any coin collection. They are coins that have been produced with some type of mistake during the minting process, resulting in variations that are different from the intended design.
Error coins can occur in various ways, from blank planchets that were not fed into the press correctly, to coins that were struck twice, to off-center strikes, and more. Some of these errors are relatively common, while others are more rare and valuable.
Let's explore the most common types of error coins and how they are made. By understanding the different types of errors and how they come about, collectors and enthusiasts will be better equipped to identify and appreciate these unique pieces.
Blank Planchet Errors
Blank planchet errors occur when a blank piece of metal (planchet) is not properly fed into the press during the minting process, and thus, is struck without any design or inscription. These errors can happen in various denominations (e.g., penny, nickel, dime, etc.) and can be easily identified by their smooth, plain surface.
The cause of blank planchet errors can be due to a variety of reasons. Such as a malfunctioning feeder mechanism that is supposed to feed the blank planchets into the press, or human error where a blank planchet is not properly inserted into the press. Occasionally, these errors can occur when a blank planchet is struck by a die that is intended for a different denomination.
To identify a blank planchet error, coin collectors should look for coins that have a smooth surface without any design or inscription.
Struck Through Errors
Struck-through errors occur when a foreign object, such as a piece of debris like, lint, a piece of thread or even a small screw becomes lodged in the press during the minting process and is struck into the coin. These errors can happen in various denominations and can be identified by a distinctive mark or indentation on the surface of the coin.
Struck-through errors can vary in rarity and value depending on the denomination, the specific object that was struck into the coin, and the condition of the coin. For example, a struck-through error that features a clearly visible foreign object will be more valuable than one with a small and less visible mark. To identify a struck-through error, look for coins that have a clear indentation or mark on its surface caused by a foreign object.
Double Struck Errors
Double struck errors occur when a coin is not properly ejected from the press after the first strike, and is then struck again. This results in a coin with two sets of design and inscription, with one set being off-center or overlapping the other. These errors can happen in various denominations and can be identified by the presence of two sets of design and inscription on the coin.
The cause of double struck errors can be due to a malfunctioning ejection mechanism, human error where the coin is not properly removed from the press, or the coin being stuck in the collar and struck again.
Double struck errors can vary in rarity and value depending on the denomination and the condition of the coin. For example, a double-struck error that features a clearly visible and well-defined second strike will be more valuable than one with a faint or poorly defined second strike.
Off-Center Errors
Off-center errors occur when a coin is not properly aligned in the press during the minting process, resulting in a coin with the design and inscription off-center and partially missing on one side. These errors can happen in various denominations and can be identified by the presence of a partial design and inscription on one side of the coin.
The cause of off-center errors can be due to a malfunctioning feeder mechanism that is supposed to align the coin in the press, human error where the coin is not properly inserted into the press, or the coin being struck by a die that is not properly aligned.
Off-center errors can vary in rarity and value depending on the denomination, the specific degree of off-centering, and the condition of the coin. For example, an off-center error that features a clearly visible and well-defined off-center strike with the date will be more valuable than one poorly defined off-center strike.
Die-Crack Coins
A die crack is a type of coin error that occurs when a coin is struck using a damaged or cracked die. A die is a metal stamp that is used to strike coins, and it has the design elements of the coin on it. When a die is damaged, it can cause a crack to appear on the surface of the die. When the die is then used to strike coins, the crack will appear as a raised line on the surface of the coin.
Die cracks can appear in a variety of locations on a coin, including the fields (background areas) or the devices (design elements) of the coin. They can vary in length and thickness, and can be straight or curved. Some die cracks may be small and barely visible, while others may be large and prominent.
Die cracks are caused by a variety of factors, including metal fatigue, corrosion, and improper storage. The most common cause of die cracks is metal fatigue, which occurs when a die is used to strike many coins. The repeated impact of striking the coins can cause the metal of the die to weaken and crack.
The value of a coin with a die crack depends on the rarity and severity of the die crack, as well as the overall condition and rarity of the coin. Die cracks are errors and are of interest. They can be worth more than the face value of the coin, although the amount of premium is not as high as in the case of doubled-die coins. Not all die-cracked coins are valuable, and some may be worth only a small premium over the coin's face value.
Re-Punched Mint Marks
A re-punched mint mark (RPM) is a type of coin error that occurs when a mint mark, which is a small letter or symbol indicating the mint where a coin was struck, is punched or stamped onto a coin multiple times. This can happen when the mint worker accidentally punches the mint mark in the wrong location, then punches it again in the correct location. This results in a faint image of the original mint mark being visible next to the clearly struck mint mark.
RPMs can be found on a variety of coins, including Lincoln cents, Jefferson nickels, and Roosevelt dimes. The value of a coin with an RPM depends on the rarity and severity of the RPM, as well as the overall condition and rarity of the coin. Not all RPMs are valuable, and some may be worth only a small premium over the coin's face value. A coin collector or coin expert can give an accurate estimate of the value of an RPM coin.
It's worth noting that RPM is a subtype of “overmintmark” errors. Overmintmarks happen when the mint mark is applied to the die in the wrong place, either accidentally or deliberately, and then the coin is struck with the die.
Die-Cap Coins
A die-cap is a type of coin error that occurs when a coin is struck using a die that is not properly aligned with the collar, which is the ring of metal that surrounds the edge of the coin blank and helps to shape the coin as it is struck. This can cause the metal of the coin to flow over the top of the die, creating a cap-like shape that covers the top of the die.
Die-caps are caused by a variety of factors, including worn dies, damaged collars, or an incorrect striking pressure. They can happen when the die is not properly secured in the press, or when the collar is not properly adjusted. They can also occur when the die is worn and the design on it has become shallow, causing the metal to flow over the die.
Die-caps are generally round or conical and can vary in size. They often appear to be a flattened coin with the design elements pressed into the metal. They can also appear to be a coin that is stuck to another coin. The design elements on a die-cap are often distorted, and the coin will appear to have a raised rim. The value of a die-cap coin depends on the rarity and severity of the die-cap, as well as the overall condition and rarity of the coin. It's worth noting that die-caps are also known as “stuck-caps” and “cap-over-coin” errors. They are considered to be among the most dramatic and visually striking of all mint errors.
Brockage
A brockage is a type of coin error that occurs when a coin is struck using a die that has an impression of another coin on it. This happens when a coin is stuck in the coin press and then becomes lodged between the die and the planchet (coin blank). When the next planchet is inserted into the press and struck, it receives an impression of the previously struck, and now stuck, coin on one side. The opposite side of the coin will have the intended design, but it will be incuse (recessed) in the coin's surface.
The design elements of a brockage coin will be the mirror image of the design elements that are on the previously stuck coin. The coin will have a raised rim and the design elements will be recessed into the surface of the coin. Brockages can be found on a variety of coins, including Lincoln cents, Jefferson nickels, and Roosevelt dimes. The value of a brockage coin depends on the rarity and severity of the brockage, as well as the overall condition and rarity of the coin.
It's worth noting that brockages are also known as “incuse strike” and “mirror brockage” errors.
Cud Errors
A cud error, also known as a “die break” or “die chip”, is a type of coin error that occurs when a small piece of the die breaks off, leaving a raised area on the surface of the coin. This can happen when a die is overused, or when the metal of the die is of poor quality. A cud is a raised area on the surface of a coin that is caused by a piece of the die breaking off.
Cud errors can occur on any part of the coin, including the obverse (front) or the reverse (back), but are generally along the edge of the coin. They can vary in size and shape, and can be straight or curved. Some cuds may be small and barely visible, while others may be large and prominent. They can also have a variety of shapes such as round, irregular, and crescent shaped.
Cuds are caused by a variety of factors, including metal fatigue, corrosion, and improper storage. The most common cause of cuds is metal fatigue, which occurs when a die is used to strike numerous coins. The repeated impact of striking the coins can cause the metal of the die to weaken and crack. Corrosion can also cause a die to crack, as can improper storage of the die.
The value of a coin with a cud error depends on the rarity and severity of the cud, as well as the overall condition and rarity of the coin. They may be worth more than the face value of the coin. However, not all cud errors are valuable, and some may be worth only a small premium over the coin's face value.
Lamination Error
A lamination error is a flawed planchet defect. They are caused by impurities in the metal or internal stresses. The results are coins that may have parts discolored. It may appear the coin is peeling or splitting, or simply be uneven surfaces like bumps on the surface of the coin. As with other errors, they may be worth more than face value, depending on the severity of the error and the overall conditional quality of the coin.
Clipped Planchet
These are dramatic errors resulting from a bad feed of the metal strip through the blanking machine. A punch may overlap the forward edge of the metal, causing a straight clip. Other times, a punch may strike the strip overlapping the whole left by the previous strike. Either way, the result is a missing part of the coin. Clipped planchet errors are usually worth more than face value, again, depending on the severity of the error and the overall condition of the coin.
Missing Edge Lettering
Missing edge lettering on a coin is a type of error that occurs when the lettering or design elements on the edge of a coin are not properly struck. This can happen for a variety of reasons, including worn or damaged dies, improper alignment of the coin blank in the press, or issues with the striking pressure.
The value of a coin with missing edge lettering depends on the rarity and severity of the error, as well as the overall condition and rarity of the coin. Missing edge lettering errors are of interest to coin collectors and can be worth more than the face value of the coin.
Doubled-Die Coins
Finally, a “doubled-die” coin is a coin that has been struck using a die that has a design element that appears to be doubled. The doubling effect can appear on any part of the coin design, including the date, lettering, and devices (such as stars or eagles). A true “doubled-die” coin occurs in the creation of the die, not because it is double struck in the press.
The value of a doubled-die coin can vary depending on the rarity and severity of the doubling on the coin. Some doubled-die coins are more valuable because they have a more dramatic doubling effect, or they are from a rare year or denomination. Some of the most famous and valuable doubled-die coins include the 1955 Lincoln Wheat Penny and the 1972 Lincoln Cent.
Error coins are a unique and fascinating aspect of the coin collecting hobby. Error coins occur only in the minting process. Each type of error coin is caused by a different reason, such as a malfunctioning feeder mechanism, foreign objects getting caught in the press or human error. The rarity and value of error coins varies greatly depending on the denomination, the specific error, and the condition of the coin. There is a large and growing number of coin collectors who specialize in collecting only error coins. To learn more about this great hobby, read Quick Guide to Coin Collecting, 2nd Edition.
Understanding the different types of errors and how they come about can help collectors and enthusiasts to identify and appreciate these unique pieces, and may also be valuable in coin collecting and investing.
