Misplaced Mint Mark: Some state quarters have mint marks (e.g., "D" for Denver or "P" for Philadelphia) that are incorrectly placed. Rare errors, like misplaced mint marks, can be highly valuable to collectors.
Doubled Die Errors: These occur when the coin is struck twice with slightly different alignments. This can create visible doubling of the text or images on the quarter, making it a sought-after collectible.
Off-Center Strikes: If a quarter is struck off-center, it can have parts of the design missing or overlapping. These errors are less common and can be valuable due to their rarity.
Reverse Die Cracks: Cracks on the reverse side of the coin’s die can create noticeable lines or gaps in the design on the coin. These die cracks can make a quarter more valuable to collectors.
Clipped Planchets: Sometimes, the metal blanks used to make coins are improperly cut, leading to quarters with missing segments. These clipped planchets are rare and can be worth more than standard quarters.
Error in State Design: Occasionally, quarters have errors in the state-specific designs, such as incorrect inscriptions or design features. These design errors are often rare and collectible.
High-Relief Errors: High-relief errors occur when the design on the quarter is unusually prominent due to issues with the striking process. These can make the coin stand out among others and increase its value.