NNP

Wear.  The abrading away of minute layers of metal surface of a coin from its circulating in commerce and handling. The actual amount of metal removed is not that great. A study conducted in Great Britain revealed that coins in normal circulation for 20 years abrade only 1 to 1.5% of their original weight in that period. However, if a coin is carried long enough, in pocket or purse (as a pocket piece), it will wear smooth, abrading down to a slick disk. Wear occurs from every physical contact a coin experiences: contact with flat surfaces (high point abrasion) to contact with all other objects – sharp, hard, pointed (as keys) – all inflict damage either as surface abrasion or nicks. Dropping the coin abrades the edges; dropping other objects on coins hastens surface abrasion.

At the beginning of the 20th century the United States Mint accepted several kinds of U.S. coins to be recoined. This included:  defaced coins, coins issued before 1834, and coins worn more than one-half of one percent by weight. It was estimated that, like the British study mentioned above, twenty year's wear would abrade this minute percentage. Any amount greater than that would subject a coin to be melted and recoined in current coins.

Wear affecting coin design.  For centuries coin designers have sought to change coin design to inhibit abrasion. Raised rims and borders was the best solution. If the entire design is no higher than the rim, it must, by necessity wear first before the design is affected. Because only the topmost layer of metal abrades, the high points are what a collector or numismatist examines first to determine condition. The more wear, the lower the condition – from uncirculated down to almost uncirculated, down to extremely fine, down to very fine, down to fine, down to very good, down to good, down to poor. Each layer of metal – a tiny percentage of a coin's total metal mass – removed from the surface affects this factor of condition.  See abrasion, condition.

Wear is a natural enemy of any coin. If a coin is discounted in a commercial

transaction because of this wear, the amount discounted is called agio.

Die wear.  Understandably the constant compacting of dies striking blanks over and over for thousands of times produces wear on the face of the die. Fresh dies have sharp angular corners of relief and lettering. In long production runs these sharp features become somewhat indistinct despite the fact that once a die is placed into production it becomes work hardened. The face also becomes bright, from striking, often in contrast to the surface on the remainder of the die.

Wear on dies is not always uniform over its entire face – there are areas of stress,

usually near the rim –and the combination of wear and stress can seriously affect the surface configuration. Yet we have seen production runs upwards of a million pieces struck from a single die.  See wearlife, worn die.

excerpted with permission from

An Encyclopedia of Coin and Medal Technology

For Artists, Makers, Collectors and Curators

COMPILED AND WRITTEN BY D. WAYNE JOHNSON

Roger W. Burdette, Editor