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    

1910 Off Center Error Liberty Head Nickel Choice Uncirculated1955/55 Ddo Lincoln Cent Wheat Penny, Doubled Die Obverse, Nice Bu++ Key Date!Key Date 1955 Doubled Die Lincoln Wheat Cent Error Xf1955/55 Ddo Lincoln Cent Wheat Penny, Choice Bu++, Highly Desired Mint Error!Key Date 1937-d Three Legged Buffalo Head Nickel Error Ngc Au581991 Ngc Silver Eagle S$1 Obverse Struck Thru Mint Error Ms641918/7-d Overdate * Pcgs Vf35 * Buffalo Indian Head Nickel 5c Rare $6,900+ Error1802/1 $1 Pcgs Vg Details Draped Bust Silver Dollar, Overdate Error, Scarce Type1942 / 1 Mercury Dime Pcgs Xf-40 (super Rare & Unusual & Nice Silver) Fs-error!2008-w (burnished) Silver American Eagle (w/box & Coa) Uncir Reverse Of 20071955 Double Die Lincoln Cent Pcgs Au 531937-d Buffalo Nickel, 3-legger, Always In Demand Choice Au Key Date Mint Error!2000 Double Struck Lincoln Memorial Cent Error Anacs Ms64rdVery Rare 1c Error 1961 Lincoln Cent Double, Multi Struck (2 Dates) Ms #9611980 Double Struck Cent Both Strikes Off Center Ms64rb Ngc1863/1864 Civil War Error/both End/old Window Bank Wrapped Wheat Cent Penny Roll1998 Mint Error 50% Uniface Obverse And B/s Broadstruck 1c Ms67rd Lincoln Cent1808 Silver 50c Capped Bust Half Dollar, Mint Error Or Intentional? 207 Yrs Old1971-d Double Struck With Brockage Nickel Au58 Pcgs1883-o Morgan Silver Dollar - Rotated Dies ** Ngc Certified Mint Error Vg 8Rare 1967 Lincoln Penny Obverse Lamination Mint Error Ngc Ms 63 Bn Must See (202001-p $1 Sac Improperly Annealed Plan - Pcgs Ms-68 2004-d Wisconsin Error Variety Low & High Leaf Ngc Ms 65 #1898871-(043-045)1966 Kennedy Vp-006 Double Die Obverse Ngc Sms 67 Vp-006 * Rare! *Ngc Ms 65 2007 Washington Dollar Mint Error Missing Edge Lettering B925Estate Mixed Cent Roll With Error Cwt Civil War Token / Vf 1901 Indian Cent St1995 Quarter 55% Off Center Bu--no Reserve1883 O Silver Dollar Rotated 45 Degrees Au-- No ReserveOff-center Lincoln Wheat Cent 1909-1958 Style; Brown Unc.!(2007) George Washington $1 Error Missing Edge Lettering – Pcgs Ms65 – Very Nice1999 & 2000 Lincoln Cent Uncirculated Off-center 1c Error Coins2000 P Ma State Quarter Mint Error D/s 2nd Strike 25% Off Center Pcgs Ms 64!!!1893-cc Morgan Dollar - Extra FineNgc Certified Proof 66 1964 Kennedy Half Dollar * Accented Hair * Silver Error 1964 Dime 40% Off Center, Bu8pc Roll Of 1954-s S/s Washington Silver Quarter ~ Error Variety ~ Bu+1966 Kennedy Double Die Obv - Doubled Profile Ngc Sms 66 Cameo * Rare! *1998 Linc. 1¢ Double Struck & Lrg. Broadstrike 1966 Kennedy Double Die Obv - Doubled Profile Ngc Sms 67 * Rare! *1971 S Ddo Proof Lincoln Cent Ngc Pf 66*rd (star) Fs-032/fs-101 Double Die Error1920 Buffalo Nickel Split After Strike Planchet Error Coin Scarce Unusual1900 Barber 50 ¢- Partial Collar Error Ngc 1787 Connecticut Colonial Copper Off Center Struck ObverseDateless Cud Washington Quarter Major Error Coin ~ Wqc-nd-26Gem Proof 1960 Silver Roosevelt Dime W/ Double Die ObverseDie Crack One Cent Penny Error - 19??2000-d Ken. 50¢ Improperly Annealed Plan- Pcgs Ms-65 (2007) John Adams $1 Error Dbl & Overlapped Edge Lettering – Ngc Ms65 –very Nice1973 D Nickel Struck On A Copper Cent Planchet 3.1 Gr. Us Mint Error Coin2007 Us Presidential Dollar $1 - George Washington - Pcgs Ms65 - Mint Error1957-d 1c Off Center, Mint ErrorDouble Struck Lincoln Cent, 2nd Strike 60% Off Center, Uniface Reverse, 1968 Kennedy Half Dollar Error Straight Clip Ngc Ms622003 Ngc Missouri State Quarter Dolllar Error Waffled Mis Struck Waffle Coin NrRare Date 1979 5c On 1c Planchet Nickel Struck On Cent Mint Error Coin1883 Cc Gsa Dollar Mint Error Triple Rim Clip Morgan Dollar In Gsa Holder! Wow!Sms Kennedy Half Dollars Lot One Pcgs 1966 Sp66cam + One Pcgs 1967 Sp66+cam Monster Clashed Die 1967 Jefferson Nickel Ngc Au58 Mint ErrorMint Error 1983 Lincoln Cent - Pcgs Ms64 - Stk On Unplated Zn Plan1953-s Lincoln Wheat Cent Ngc - Ms 66 - Red - (( Mint Error Coin ))