Die Over Polishing

Die Over Polishing occurs during the minting process. A coin die is a hardened piece of metal used to strike coin blanks to create the coin’s design. Over time, these dies wear down and can develop imperfections such as cracks, clash marks, or other flaws. In an attempt to extend the life of a die or improve its performance, mint workers may polish the die. However, excessive polishing can inadvertently remove small details from the die’s design. When this over polished die is used to strike coins, it results in coins that lack certain design elements or have unusually smooth areas where there should be fine details.
The impact of Die Over Polishing on coins can vary significantly, leading to a range of situations that collectors and numismatists find both intriguing and challenging. Here are some common manifestations:
Missing Design Elements: The most direct effect is the absence of small, intricate design details. On heavily over polished dies, elements such as leaves, letters, or even facial features might be partially or completely missing.
Smooth Surfaces: Areas of the coin that should have fine textural details may appear unnaturally smooth or polished, giving the coin a washed-out look.
Weak Strikes: Although not directly a result of the over polishing itself, the diminished details can give the appearance of a weak strike, as less metal flows into the shallower recesses of the die.
Die polishing lines: When a die is subjected to over-polishing, it may leave subtle scratches or fine lines on the smooth surface of the die. During the minting process, these tiny lines are transferred to the final coin surface in the form of raised fine lines.