Identifying Error Coins & Coin Error Values
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Identifying Error Coins & Coin Error Values

Steven Cochran
Published June 01, 2010

Modern coin minting is a highly technological process. On occasion however, even the most advanced processes break down, and mistakesare made.

Errors in coin manufacturing are manifested in a number of different ways, the mostdocumented of which are detailed here:

  • Planchet Errors: The planchet error occurswhen the wrong planchet (coin blank) is fed into the coin-striking press. What resultsis the incorrect design appearing on a particular coin. Examples of this includecent artwork appearing on dime pieces or quarters on dimes.

  • Strike Errors: Strike errors are causedby a flaw or malfunction in the press machinery. The two most common examples ofstrike error are:

  • Broadstrike: This happens when the collarpiece, that is, the part of the press responsible for the maintaining the shapeand size of the coin during the strike is damaged or missing, causing either theedges of the coin to be flawed or the dimension of the coin to be irregular.

  • Misfeed: As the name implies, misfeedsare the result of the planchet not having been properly inserted into the press.If not perfectly aligned, strikes may occur in positions on the planchet not intendedto be struck or on the edges of a previous strike, resulting in “clipped” coins.Such examples can be identified by their missing portion of the coin.

  • Defective Die: The “die” is the portionof the press responsible for striking the image into the planchet. It is comprisedof hardened steel and contains the image (in reverse) intended to appear on thefinished coin. Throughout the course of their usage, die can become worn or damaged.Coins minted using defective die can be easily identified as they will have eithera raised line across their surface, resulting from a crack in the die or missingartwork altogether stemming from a completely broken die.

  • Brockage: Brockage errors usually resultfrom a coin sticking to its die after the strike. What results from each strikeuntil the problem is remedied is a coin with identical images, with one concaveinstead of convex, on both sides.

  • Overdate: In the past, it was commonto use a die until it broke. Because they could last for several years, it becamenecessary to change the date on the coin after it was minted. To do this, minterssimply struck the coin again with a new number over the last digit in the date.What resulted was a coin that could be seen to have two numbers in same positionon the coin.

“Error Coins,” as the coins resulting from the above mistakes in striking are collectivelyknown, have a numismatic market all their own. Because these errors, especiallyin modern minting, are extremely rare, coins which contain them are valued at ahigh price – often above other rare coins.

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Steven Cochran

Steven Cochran

Precious Metals Market Analyst | BS University of South Florida (2002)

A published writer, Steven's coverage of precious metals goes beyond the daily news to explain how ancillary factors affect the market.

Steven specializes in market analysis with an emphasis on stocks, corporate bonds, and government debt.