Generally speaking, there are two extremes in U.S. coin collecting. The first is to search for that Holy Grail coin in great condition, such as an 1856 gold Double Eagle that was minted in New Orleans and is graded AU-55, or a 1873 Morgan silver dollar, minted in San Francisco and graded MS-65.

People who love error coins are at the opposite end of the perfection spectrum, though they often pay top dollar for their treasured damaged goods. Errors are coins that didn't turn out quite as the mint intended, with clipped edges, overstruck dates, and quirky imperfections.

One of the many things that makes error coins so interesting is that they encourage the coin collector to become knowledgeable about the minting process itself, since all error coins are the result of something going awry at the mint.

At the top of the error pyramid are hub errors. The hub is the piece of hardened steel that is used to create a die, which is the metal punch that delivers a coin’s design onto a blank, or planchet. The design on the hub is the same as that on the coin, but the die is a mirror image, which means it transfers a correctly oriented image onto the final coin.

Until recent advances in minting technologies, it had taken two, three, and sometimes four strikes of a hub onto a heated die to successfully transfer the hub’s image. That left a lot of room for error, the most common of which occurs when the first and second strikes of a hub on a die are not perfectly aligned. In these cases, a doubled die is created, resulting in a coin whose elements repeat.

In rare cases, a double denomination can be created, such as in the case of the 11-cent denomination. Struck coins are sometimes transported from coining presses in bins that are later used to transport planchets. In this case, a bin full of struck dimes was reused to transport penny planchets. A few dimes that had become stuck at the bottom of a bin were struck again as cents along with all the planchets. The resulting 11-cent double denominations are larger than dimes but smaller than pennies. Coins that have the most detail are generally the most expensive, but collectors should mis-merit the value of a coin that's not perfectly round.

Another classic example of a doubled-die coin is the 1955 Lincoln Wheat penny, which some experts refer to as an error but others call a variety because so many of them made it into circulation. When the doubled die for this coin struck the obverse, or face, of the planchet, doubling occurred on the date and legend. As a result, the coin looks oddly out of focus...

Since the mistake was not caught until the coin was in circulation, no one knows for sure how many were made—just under 331 million Lincoln Wheats were minted that year, but only 15,000 doubled examples are known to exist. Whatever their number, the coin is credited with igniting an interest in error coins, as well as being a favorite target of forgers.

For collectors, only Lincoln Wheats with clearly defined doubling are considered valuable. For example, a coin with less pronounced doubling, known as a “poor man’s doubled die,” can be picked up for under a quarter, while coins whose doubling is clear and crisp sell for $1,000 and up.

Worn-out dies are also a problem. If the die is cracked, those cracks will also appear on a coin. Similarly, if a small section of the die has broken off, then a like-sized section of the coin will remain unstruck. This frequently happens along the edge of a coin and is referred to as a cud.

Even if the die is not compromised, many things can go wrong when it strikes a planchet. One relatively common occurrence is a broadstrike error, which is when the collar die (the punch that imprints the planchet with the design on the coin’s edge) fails to strike the coin at all, leaving it without any edging and a flattened-out center image.

Sometimes a die will strike a planchet wildly off center. In these situations the die is not the culprit; rather, there was a problem with the way in which the planchet was moved into position in the press. In extreme cases, an off-center coin will remain in the press to be struck a second time or more. In general, coins with multiple errant strikes are more prized by collectors than those with only one.

One of the most intriguing types of errors is a coin that has been struck properly but onto a clipped planchet, which is created when something is out of whack with the machine that stamped them out in the first place. For example, the machine stamps out a row of planchets too close to the one above it, the resulting bad blanks will look like someone took a bite out of them.

Planchet errors are also caused by stamping too close to the edge of the planchet’s source sheet metal, producing a blank whose otherwise perfect circular shapes are interrupted by straight edges on one side.

While production practices at U.S. Mints have improved in recent years, thus eliminating many of the most common historical errors, contemporary coins have not been immune to the occasional mistake.

For example, a crack in the die used to strike the reverse of the 2009 Formative Years Lincoln cent, which depicts the future president taking a break from chopping wood to catch up on his reading, can be seen at the bottom of the coin, through the second “U” in “Pluribus,” and up into the young man’s boot.

Because the crack resembles a bootstrap, this error, which may be widespread enough to be considered a variety, is known as the Bootstrap Lincoln Cent.

Even stranger are the die flaws that produced three different types of Wisconsin state quarters, all from the Denver mint, in 2004. The variations appear on the coin’s reverse and affect the number and orientation of the leaves on an ear of corn.

In the normal coin, the ear has a leaf on the left that arcs up and then down to the left. In a variation of that coin, there appears to be a second leaf below that one, rising out a wheel of cheese that sits below the ear of corn. A third 2004-D Wisconsin quarter shows that same extra leaf, only this time it is bent down and to the left. Inexplicable.

Finally there are so-called blundered dies, which refer to dies that were simply made incorrectly—unlike a doubled die, a blundered die suggests human rather than mechanical error. The most famous example of this sort of error is the 1982 dime, which was minted in Philadelphia but failed to identify itself with the “P” mint mark. An estimated 14,000 to 15,000 of these error dimes made it into circulation, which makes it a popular coin for many collectors.

About our sources | Got something to add?

▼ Expand to read the full article ▼

Best of the Web (“Hall of Fame”)

Legendary Coins and Currency

Legendary Coins and Currency

This online exhibition from the Smithsonian's National Museum of American History is a great way to get an overview… [read review or visit site]

Society of U.S. Pattern Collectors

Society of U.S. Pattern Collectors

Home to the Society of U.S. Pattern collectors, this well-organized site provides in-depth information on pattern c… [read review or visit site]

Clubs & Associations

Other Great Reference Sites

Most watched eBay auctions    

1922 No D, Lincoln Cent Wheat Penny Strong Reverse, Pursued Key Date Error, Au++1955 1955/55 Ddo Doubled Die Obverse Pcgs Ms62 Bn Lincoln Wheat Cent 1c $2,350++1942/1 Mercury Silver Dime Pcgs Xf40, Key DateRare 1972 Double Die Cent Uncirculated 1c Bold Strike1942/1 Mercury Dime, Highly Coveted Key Date Mint Error, Choice Xf++/au!1817 Capped Bust Silver Half Dollar -obv. Die Break Error- Au/unc1937-d * 3 Legs Legged * Pcgs Xf40 * Cac * Indian Head Buffalo Nickel 5c $1,200+Error??? & Lincoln Tail Ends / Vintage Window Wrapped Wheat Cent Penny Roll1823 Capped Bust Silver 50 Cents -rev. Die Break Error- Choice Uncirculated1804 Draped Bust Half Cent -10% Off Center Error- Vf+ Rare Early Error!1942/41-d Mercury Silver Dime Ngc G6, Key DateDouble Struck Washington Quarter Error Coin1937-d Buffalo Nickel, 3-legger, Highly Demanded Au++ Key Date Mint Error!1955 Double Die Lincoln Wheat Cent No Reserve.1992-p Dime Double Struck Bu - See Other Auctions 1996 Huge Nickel Siz Broad Struck Error Roosevelt Dime Ch Bu O/c Coin No Reserve1972 1c Ddo Fs-104 (033.54) Bn Lincoln Cent Buffalo Nickel Split Plachet Error Free S/h1823 Capped Bust Half Dollar, Patched 3, Avidly Pursued Au+ Better Date!Off Center Lot Of 17 Off Center Lincoln Memorial Cents *free Shipping*2016-w $10 1/2 Oz. Gold First Spouse - Reagan Mint Error Rev Ms 69 Sku419181966 Kennedy Double Die Obv - Doubled Profile Ngc Sms 68 * Top Pop - Rare! *2 X 2000-p Nickels Off Center Stretch Strikes Gem Bu - See Other Auctions 1966 Kennedy Double Die Obv - Doubled Profile Ngc Sms 67 * Rare! *2015 $50 1 Oz Gold Buffalo Mint Error Rev Struck Thru Ngc Ms69 Buff Lbl Sku419241894 Double Struck Indian Cent Ngc Vg10 Bn2004 D Icg Ms65 Wisconsin Wi Quarter Extra Leaf High Rare1968-s Double Die Obv. Kennedy Half Fs-101 Pcgs Pr 68 *price Guide $400 Pop 9/2*2007 Icg 1st Release Double Edge Lettering Error John Adams Dollar$1 Coin No Res2 1984 Quarters - Error - StruckOff Center Lot Of Three Full Date Lincoln Memorial Cents *free Shipping* 19821885-cc Morgan Silver Dollar Anacs Ms631974 Cent With Athiest Cud Bu Rb - See Other Auctions Dateless Clad Washington Quarter Cud ~ Major Die Break ~ Major Error Coin1985-p Washington Quarter 10% Off-center1996 Error Huge Off Center Roosevelt Dime Ch Bu Coin #43 Of 100 Auctions NrPakistan One Rupee Km#67 Massive Reverse Die Cap - Very Dramatic!2001 Double Denom 11 Cent Pc Lincoln Cent Struck On Dime Planchet Anacs 65 Error2000 P Anacs Ms65 Gem Off Center Toned New Hampshire State Quarter Mint Error1878 8tf Morgan Silver Dollar, Van Double Die Reverse, Very Nice Coin.No Date Uniface Lincoln Memorial Penny With Partial Collar And Railroad Rim1985 Quarter - Error1997-p Roosevelt Dime, Off-center Planchet, Highly Coveted Mint Error!$1 1974-d Eisenhower Error: Struck On 40% Silver Planchet Pcgs Au * AvenuecoinPcgs Ms-64+ 1878-s Vam-19a Cap Band Gouge,over Polished Rev.r-6 Morgan $! *naohLincoln Penny 11 Offset Errors And 3 Clipped Errors1885-o Morgan Silver Dollar/ Ngc-ms63/obv Lamination/ Mint Error/1051057951875 Indian Head Cent. Error. Cud. 959191997 Lincoln Penny Mint Error Broadstruck Ms 67 Rd 1c Ngc Certified1972-p Lincoln Cent Ms64rd Pcgs Ddo Fs-103 Double Die Obverse Cherrypicker Var1968-s Double Die Obv. Kennedy Half Fs-101 Ngc Pf 68 * Rare Beauty!1883 O $1 Silver Morgan Dollar Error Coin Rotated Die Anacs Au 501983-p Nickel Cud Die Break Mint Error Very Fine+ Reverse Lamination Error 1853 Var. 1 Three 3c Silver Trime Type Coin1883 Repunched Date Ms-62 No Cents Anacs Liberty V Nickel! Lqqk **no Reserve**2016 Lincoln Shield Cent Red Off Center Mint Error 1963 D Lincoln Cent Error: Triple Struck Front & BackStruck-thru Thinning Die Cap 1986-p Pcgs Ms62 Jefferson Nickel Error1863 Indian Head Cent Double Error Rare Rim Clip Die Break Anacs Au 551886 Ms64 Morgan Silver Dollar Ngc Certified - Toned - Very Nice !