Coin collecting comes with a vocabulary of its own. Terms like die chip, mintage, obverse, planchet, and doubled die can be confusing when you're first starting to look more closely at your coins.
Here are some of the most common coin collecting and mint error terms and what they mean.
Circulated
A circulated coin is a coin that has been released for everyday use. Circulated coins often show wear from handling and transactions.
Clashed Die
A clashed die occurs when the obverse and reverse dies strike each other without a planchet between them. Parts of one design can be transferred to the opposite die and later appear on coins struck by those dies.
Cud
A cud is a raised area on a coin caused by a major break in the die that involves the edge of the die.
Cuds can vary considerably in size and appearance.
Die Break
A die break occurs when part of a coin die breaks or fails. Coins struck afterward may show raised areas where the damaged portion of the die is located.
Die Chip
A die chip is a small break in the surface of a coin die. Metal flows into the damaged area during striking, leaving a small raised area on the finished coin.
Die Crack
A die crack is a crack that develops in a coin die. It usually appears as a raised line on coins struck with the damaged die.
Die Variety
A die variety is a recognizable difference created by the die used to produce a coin rather than by damage occurring after the coin was struck.
Doubled Die
A doubled die is a die variety in which part of the coin's design shows genuine doubling created during the die-making process.
The correct term is doubled die, not "double die."
Edge
The edge is the outermost side of a coin between its obverse and reverse. Depending on the coin, the edge may be plain, reeded, lettered, or otherwise designed.
Error Coin
An error coin is a coin produced incorrectly because something went wrong during the minting process.
Errors can involve the planchet, dies, or the actual striking of the coin.
Face Value
Face value is the monetary denomination assigned to a coin, such as one cent, five cents, or 25 cents.
A collectible coin can be worth substantially more than its face value.
Grade
A coin's grade describes its condition. Grading considers factors such as wear, marks, luster, strike, and overall preservation.
Key Date
A key date is a coin from a particular date and often mint that is significantly scarcer or more desirable than most other coins in the same series.
Mint Error
A mint error is a mistake that occurs during the production of a coin.
Mint errors should not be confused with damage that occurs after a coin leaves the mint.
Mint Mark
A mint mark is a letter or symbol identifying the mint facility where a coin was produced.
For example, modern U.S. coins may carry a P for Philadelphia, D for Denver, S for San Francisco, or W for West Point.
Mintage
Mintage is the number of coins of a particular type, date, and mint produced.
A low mintage can contribute to scarcity, but it does not automatically make a coin valuable.
Missing Clad Layer
A missing clad layer is an error in which one of the outer metal layers of a clad coin is missing.
The affected side can have an unusual copper-colored appearance and the coin may weigh less than normal.
Numismatic
Numismatic describes coins and related objects valued or studied for characteristics beyond their metal content.
Numismatist
A numismatist is someone who studies or collects coins, currency, medals, tokens, or related objects.
Obverse
The obverse is the front or "heads" side of a coin. It usually contains the coin's primary portrait or design.
Off-Center Strike
An off-center strike occurs when a planchet is not properly centered between the dies when struck. This causes part of the design to be missing while leaving part of the planchet unstruck.
Planchet
A planchet is the prepared metal blank that becomes a coin when it is struck by the dies.
Post-Mint Damage (PMD)
Post-mint damage, often abbreviated PMD, is damage that happens to a coin after it has been struck.
Scratches, dents, cuts, corrosion, heat damage, and other alterations can sometimes resemble mint errors but generally do not add collectible value.
Proof Coin
A proof coin is specially produced for collectors using a minting process intended to create a high-quality finish and sharply defined design.
"Proof" describes how the coin was made, not its condition or grade.
Reverse
The reverse is the back or "tails" side of a coin.
Rim
The rim is the raised border around the outside of a coin's obverse and reverse.
The rim is different from the edge, which is the narrow outer side of the coin.
Strike
The strike occurs when coin dies press the design into a planchet.
The quality and positioning of the strike can affect the appearance of the finished coin.
Struck Through
A struck-through error occurs when a foreign material or object comes between the die and planchet during striking, leaving an impression or missing portion of the design.
Uncirculated
An uncirculated coin shows no wear from circulation.
Uncirculated does not automatically mean perfect. A coin can still have marks or other imperfections from production, handling, or storage.
Variety
A variety is a coin with a recognizable design difference associated with how its die was made or modified.
A variety is different from a one-time minting error.
Why Coin Collecting Terms Matter
Understanding coin terminology makes it much easier to determine what you're actually seeing on a coin.
This is especially important with mint errors. A raised line could indicate a die crack, while a recessed scratch is more likely to be post-mint damage. A strange-looking coin isn't automatically an error, and an old coin isn't automatically rare.
Knowing the basic terms can help you research a coin more accurately before deciding whether it deserves a closer look.