Welcome to the neighborhood, Steph! The toning was caused during circulation, but there is no way of knowing exactly what caused it. In any case, the coin is damaged due to the horizontal depression on the obverse and is only worth 25c. It's a "spender"! Chris
It is considered Environmental Toning damage. And it looks like it took a huge hit I voted NO on your poll.
Welcome to CT Stephanie. Your quarter would be considered PMD, or Post Mint Damage, meaning what you are seeing happened after it left the mint and therefore not an error or collectable, just worth a quarter. Keep looking and learning.
