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    

1909/8 1909 /8 Overdate $20 Gold * Pcgs Ms63 * St Gaudens Double Eagle $6,000+++1937-d * 3 Legs Legged * Ngc Ms62 * Buffalo Indian Head Nickel 5c $3,100++ Error1999 Wide Am Cent Fs-901 Wam Red Uncirculated Scarcest Year Proof Style Reverse1911-d/d Repunched Rpm $20 Gold * Pcgs Ms65 * St Gaudens Double Eagle * $2,900++1839-o Seated Liberty Dime Pcgs Au50, F-106a Cobweb Reverse, No Drapery Large O2 Old Unusual Crazy Weird Error Odd Unknown Coin S Dime Quarter Off Center? Look1937-d Buffalo Nickel, 3-legger, Popular Variety For All Collector's, * Free S/h1938-d/d/d/s Repunched Mintmark * Ngc Ms65 * Cac * Buffalo Indian Head Nickel 5c1942/1 10c Mercury Dime Uncirculated Rare Key Overdate Error Bu Blast White!1962-d 1¢ Flipover & Double Struck Rare 1998-s Lincoln Close Am Fs-901 Pcgs Pr 69 Rd Deep Cameo! * Rare *Rare -2010 Sac $1 Missing Edge Lettering Pcgs Ms-66 1955 Double Die BuJeff. 5¢ Struck On Scrap Plan. Pcgs Ms-64 1935 Off Center Wheat CentN.d. Lg. Rev. Capped Die Jefferson Nickel Ms66 6fs By Ngc2004-d Error Wisconsin Extra Leaf High Statehood Quarter Ngc Ms-64 No Reserve1811 Large Cent - Clipped Planchet - True Auction - No Reserve !!!!!!!!!!!!1896 * Repunched Rpd Date Error $20 Gold * Pcgs Ms63 * Liberty Head Double Eagle1978 Cent Struck On Dime Planchet ~ Off Metal Wrong Planchet Major Error Coin1990 Ken 50¢ Struck 20% Off-center Pcgs Ms-65 Pcgs $1 1972 Ms64 Type 2 Pcgs Pop 508 Pcgs Price $300 Cherrypicker St 99c2008 Van Buren Presidential Dollar - Missing Edge Lettering Error - Ngc Ms651999 1c Lincoln Penny Broadstrike With Partial Brockage Error1937-d 3 Legged Buffalo Nickel Pcgs Vf35 Rare Error Indian Head Coin Three Legs1892 Barber Quarter Pcgs Au55 Tripled Die Reverse Very Rare Cherrypicker Variety1859-o Seated Half Dollar Unc Full Strike Excellent Details Mpd Error Nice Coin!Pcgs 50c 198x-p Kennedy Half 85% Off-center Ms-651972-p Lincoln Cent Ms65rd Pcgs Ddo Fs-107 Double Die Obverse Cherrypicker Var2008 Jackson Presidential Dollar (sms) - Missing Edge Lettering Error - Ngc Ms68Anacs (old Holder) 25c 1965 Au58 "struck On 5c Planchet" Looks Better Start 99c Anacs 1c 2000 Lincoln Cent Double-struck 40% Off-center Ms-65 Red2007 Mint Error George Washington Dollar Ngc Ms-65 Missing Edge Lettering1976-d 1¢ Nice Double Struck-scarce Date N.d. Deep Die Cap Jefferson Nickel Ms65 By Pcgs1897 Indian Cent--mint Error--struck 5% Off Center--pcgs-f122009 Sacagawea Dollar - Missing Edge Lettering Mint Error - Ngc Ms661888/7 Indian Cent Re-punched Date Error Cherry Pickers Variety 010 Snow 11866 25c Motto Liberty Seated Quarter. Nice Unc Coin. Great Details & Date!Pcgs 25c 1999-p Connecticut Quarter 90% Reverse Missing Clad Layer Ms-62(12) Sacagawea Or Presidential Waffled Planchets And Leftover WebbingPcgs 1865 3c Nickel 5% Off-center On T-1 Blank Vf-351970 D Struck On Dime Stock Washington Quarter Mint Error Off Metal 4.3 GramsAnacs 25c 2000 New Hampshire Quarter Double-struck Off-center Ms-64Pcgs 50c 1984-d Kennedy Half Obverse Missing Clad Layer Au-581930 Pcgs F15 Buffalo 5c - Doubled Die Reverse - Fs-803 The Rarest Ddr Of 19301977 Wash. 25¢ - Obv Clad Layer Missing Pcgs Ms-62 Ngc 50c 1953-d Franklin Half Struck Through String Au2009 Sac $1 Missing Edge Lettering Pcgs Ms-63 Huge Cud - 1863 Indian Cent Reverse2007 S Extremely Rare Proof Jefferson Dollar Waffled By The Us Mint Must See"90% Silver" Type Ii Half Dollar Blank Planchet Error 1944 Off Center Wheat Cent Bu1986 Silver Eagle F.y.i. Obverse Struck Thru Mint Error Ngc Ms67 (002)2014 25c Arches Np 5 Oz Silver America The Beautiful QuarterAnacs 1c 1999 Lincoln Cent 2-coin Mated Pair Ms-63 & Ms-642004-d Wisconsin Quarter - Extra Leaf Error (low Leaf) - Xf Extra-fine CondiionAvc- 1904-o Rotated Die Error Morgan Dollar Ngc Ms641919 Buffalo Nickel ~ Partial Collar Strike ~ Clipped Planchet ~ Pcgs Ms642009 Sac $1 Missing Edge Lettering Pcgs Ms-65