What are Error Coins?

By GovMint :

Error coins are fascinating numismatic anomalies that capture the attention of collectors and enthusiasts alike due to their unique and unexpected characteristics. These coins deviate from the standard minting process, resulting in variations such as misprints, off-center strikes, double strikes, planchet errors, and die cracks. One notable example of an error coin is the 1955 Doubled Die Lincoln Cent, where the date and lettering appear doubled due to a misalignment during the striking process. Error coins add a touch of intrigue and excitement to coin collecting, showcasing the artistry and occasional quirks of the minting process.

Sources Used:

https://www.thesprucecrafts.com/mint-error-coin-768452

https://www.thesprucecrafts.com/1955-double-die-lincoln-penny-4022936