A mule error coin is a coin or medal minted with obverse and reverse designs not normally seen on the same piece . Essentially, it’s a coin struck using dies (stamps used to imprint the designs) that were not intended to be paired together, resulting in a coin that has the front design of one coin and the back design of another.
Here’s a breakdown of what makes a mule coin a “mule”:
- Mismatched dies: The core characteristic of a mule coin is that the obverse (front) die and the reverse (back) die used to strike the coin are meant for different types of coins.
- A “hybrid” coin: The name “mule” comes from the animal, a hybrid offspring of a horse and a donkey, according to GovMint.com. Just as a mule is a mix of two species, a mule coin is a mix of two different coin designs.
- Result of minting errors: Mule coins are typically the result of accidental mistakes during the minting process, often when the wrong dies are installed in a coining press.
- Rarity and value: Mules are generally considered to be among the rarest error coins and are highly sought after by collectors, commanding high prices depending on factors like their condition and how many were produced before the error was caught. For example, a 2001-D Lincoln cent obverse with a Roosevelt dime reverse, sold for $78,000 on February 22, 2025.
- Examples: Notable examples include the 2000 Australian “mule” dollar coin (Queen Elizabeth II obverse, Mob of Roos design reverse from a 50-cent coin) and the 2000 Sacagawea dollar – Washington quarter mule (Washington state quarter obverse, Sacagawea dollar reverse).
In short, a mule coin is a fascinating and valuable error coin born from the unexpected pairing of coin dies, creating a unique “hybrid” in the world of numismatics.
What is a mule error on a coin?
Good point! A mule coin is a type of coin that has been created with mismatched dies, meaning that the front and back sides do not belong together. This results in a coin with a combination of designs that were not intended to appear together, creating a one-of-a-kind error coin with a mix of features from two separate coins.
What is mule error?
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.
How do you tell if you have a mule coin?
It’s a constructed replica. Someone has machined a quarter and dollar and put them together. A real mule just has the quarter die on the front, not a quarter inlaid into the dollar. The fact that it is silver instead of “golden” is the giveaway.
What is an example of a mule error?
Examples include HTTP:NOT_FOUND (a 404 error) and HTTP:CONNECTIVITY errors from the HTTP listener in the HTTP connector. DB:BAD_SYNTAX and DB:QUERY_EXPRESSION are errors that the Select operation in the Database connector can throw.