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Impressed Error

Impressed Error.  A striking error in which foreign matter is lodged on and impressed into the surface of a struck piece. The foreign matter comes between the die and the blank before striking; and after striking it is retained below the surface but later may or may not flake off or dislodge. Thus an unusual shaped depression on a struck surface may be evidence that some object had indeed lodged there during striking. As a collector's item it is far more interesting if the impressed object is still intact.

A wide variety of foreign objects have been found impressed on coins and medals including metal scrap of all kinds, wire, staples, diechips, bits and pieces of planchets, other struck pieces, small parts of tooling, and even blanks and struck pieces of smaller diameter. An area containing a letter or detail flaking off one piece (mostly because of a lamination error) falling on a blank and impressed into a second struck piece is called a dropped letter.

Metal shards from any source landing on a blank can be impressed into a coin; more often than not these tiny shards are not retained but fly off. This condition was once called lint marks but this term is a misnomer. A more accurate term for this anomaly is impressed shard mark. Cloth and other nonmetallic items have also been impressed as well as grease which forms wavy areas (rippled surface).

In presswork, impressed errors are eliminated for the most part by blowing compressed air over both dies and blank prior to striking. Collectors' terms for this anomaly is struck-thru and indents, the latter for a blank or struck piece impressed on a piece of larger size. When an object is purposely placed on the surface of the planchet and struck this is called impressed design (see previous entry).


NM19 {1991} Margolis (indents) p 265-270.

excerpted with permission from

An Encyclopedia of Coin and Medal Technology

For Artists, Makers, Collectors and Curators


Roger W. Burdette, Editor

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