I came across this Texas State Quarter (P) that had three small dots along side the Mint Mark - These three impressions are clean and quite deep to have been made through usage and I was wondering if you guys would take a look and tell me whether you think this happened during minting and if so how?
Those are called 'reed marks' and were made when the reeding on the edge of another coin came into contact with your coin. It is post-mint damage (PMD). It could have happened at the Mint moments after the coin was struck (e.g., freshly minted coins falling on other freshly minted coins in the coin press hopper seconds after being struck) or while new coins were being shipped to be rolled but it is still PMD.
