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    

1994-d Unc Jefferson Nickel Multiple Strike Error Coin Extremely Rare! 1943 10% Off Center Lincoln Steel Cent, Pcgs Ms62, Cool! Davidkahnrarecoins1972/72 Ddo Lincoln Cent Memorial Penny, Red, Solid Gem Bu++ Rd, Key Date Error!1813 50c 50c/uni Capped Bust Half Dollar Pcgs Vf351972/72 Lincoln Cent Memorial Penny, Strong Ddo, Gem Bu++ Key Date Mint Error!1922 No D 1c No D Strong Reverse Die Pair #2 Lincoln Cent Error Extra Fine Rare!1983 10c Roosevelt Dime No S Proof Deep Cameo Key Error Pcgs Pr68dcam Rare!Lincoln Memorial Cent Full Brockage Obverse Mint Strike Error Coin Free Shipping1917 1c Off-center Lincoln Pcgs Ms64 Rb Dramatic Bu Early Wheat Cent Error1922 No D Lincoln Cent Pcgs Graded F-15 Wheat Penny1983-p Half Off Center 10% K-3. Bu - See Other Auctions1916 - 1945 Near Complete Mercury Dime Set In Dansco Album - 77 Coins1937-d Buffalo Nickel, 3-legger, Choice Uncirculated++ Key Date Mint Error!2008 $1 J.q. Adams Missing Edge Lettering Pcgs Ms-681982 1¢ Double Struck2016-w $10 American Gold Eagle Mint Error Reverse Struck Thru Ngc Ms69 Sku45669* * 1918/7 D * Rare Overdate Error * 5c Buffalo Nickel * ^horn Detail! * *1999 Cent Double Struck On Center Normal Then Broadstruck Chbu -seeotherauctions 2008-w Reverse Of 2007 Burnished Silver American Eagle Error Coin. #3921864 Bronze Gem Uncirculated Indian Cent W/die Break Error**** 1967 Lincoln Cent Struck Off Center Mint Strike Error Coin - Free Shipping1867/67 Indian Head Penny, Very Rare Choice Fine Key Date Mint Error, Free S/h!2016 Silver Eagle Ngc Ms69 Error Obverse Struck Thru (30th Anniv Label) Cn3402017 American Silver Eagle Ngc Ms69 Er (mint Error Fingerprinted Die) Cn9372000 W Mint Error Bi-metalic $10 Library Of Congress 2016-w Gold Dime Error Obverse Struck Thru Ngc Sp69 Fr (gld Foil Blk Core) Cn3591999 Cent Reverse Capped Die Ngc Ms 65 Rd Date Brkgd On Obv!- See Other Auctions2017 $50 1 Oz. Gold Buffalo - Obverse Struck Thru Mint Error Ngc Ms69 Sku455052016 $50 1 Oz Gold Buffalo Ngc Ms69 (mint Error Obverse Struck Thru) Cn1551986 Silver Eagle Ngc Ms69 (mint Error Obverse And Reverse Struck Thru) Cn9712016-w Gold Dime Error Obverse Struck Thru Ngcsp69 Er (100th Lbl Blk Core) Cn1042016 Silver Eagle Ngc Ms69 Error Reverse Struck Thru (30th Anniv Label) Cn5591968-s Double Die Obv. Kennedy Half Fs-101 Pcgs Pr 68 *price Guide $400 Rare! *1972/72 Lincoln Cent Memorial Penny, Beautiful Superb Gem Bu++ Key Date Error!2001 American Silver Eagle Ngc Ms69 (mint Error Obverse Struck Thru) Cn9911984 Roos. 10¢ 20% O/c & Clip Pcgs 1992 American Silver Eagle Ngc Ms69 (mint Error Obverse Struck Thru) Cn9761883 O $1 Morgan Silver Dollar Rotated Die Error Nice Circulated No Reserve1989 Cent With Cud Obverse. Chbu+ - See Other AuctionsNd Cent Multistruck Broadstrike Brockage Capped Die Strike Bu+ -seeotherauctions1860 Copper-nickel - Indian Head Cent - Full Liberty - Off Center Error Strike1964 Pcgs Ms643 Brockage And Broadstruck Nickel Mint Error Great Eye AppealPcgs 1c 1988 Lincoln Cent On Dime Double-denomination Ms-641967 Double Die Washington Pcgs Sp 68 Ddo Fs 101 (026.5) * Price Guide $750 *2016-w Gold Dime Mint Error Obverse Struck Thru Ngc Sp69 Er (100th Label) Cn2631947-s/s 25¢ Rpm Fs-501 Pcgs Ms-662015-p Silver Roosevelt Dime Obv Struck Thru Mint Error Ngc Rev Pf69uc Er Cn475Nd Nickel Struck On A Phillipines 5 Sentimo Planchet 2.45g - See Other Auctions2001 American Silver Eagle Ngc Ms69 (mint Error Reverse Struck Thru) Cn9962017-p Us Lions Club Proof Silver Dollar - Ngc Pf69 Early Releases Mint Error1857 Liberty Seated Half Dollar Anacs Ef Wb-102 Misplaced Date Rare! 2017 $50 Gold Buffalo Ngc Ms69 Er Mint Error Obv Struck Thru (buffalo Lbl) Cn3331999 Silver Eagle Ngc Ms69 (mint Error Obverse And Reverse Struck Thru) Cn9871942/1 Mercury Dime 10c Pcgs Au50 Secure 1947-s/s 25¢ Rpm Fs-502 Pcgs Ms-661964 Ngc Ms63 Reverse Struck Thru Capped Die Silver Dime Mint Error1946 Pcgs Au55 Ddr Fs-801 Walking Liberty Half .99c Noreserve Double Die Reverse1966 Kennedy Double Die Obv - Doubled Profile Ngc Sms 67 * Rare! * Errors Anacs Ms=63 R/b 1984 P/ Cud Lincoln Cent Nice !! 1980 1¢ Double Struck