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    

1943-d Steel 1¢ Double Struck-pcgs 1937-d 5c 3 Legged Buffalo Key Error Nickel Choice Au+ Full Horn Three Leg Rare!1955/55 Lincoln Cent Wheat Penny, Ddo, ** Seldom Seen In Choice Bu++ Condition!1983 1c Lincoln Cent Double Die Reverse Ddr #1 Ngc Ms67rd Red Gem++ None Higher!1972 1c Lincoln Cent Doubled Die Ddo #1 Error Pcgs Ms65rd Gem Red Ogh Rare!1979 5¢ Struck On Cent Plan. Pcgs Ms-63rb 1955 Double Die Ms-61 Icg Certified Lincoln Wheat CentRare 1974 Cent Struck On Dime Double Denomination Mint Error Penny On 10 Cent 11 Rare 1973 D Lincoln Cent Double Struck Strike Indent Broadstrike Error Gold American Eagle 4 Coin Proof Set With Box, Display Case & Coa 1988Key 1921 Peace Dollar Ngc Ms-64 Bold Obverse Doubling (strike Error?)1970 No S Proof Roosevelt Dime Key Date Error Pcgs Pr681909 Vdb Doubled Die Obverse Lincoln Wheat Cent Error Pcgs Ms64rd1857 1c Pcgs Au 55 Flying Eagle Cent, Double Die Look, Scarce Problem Free PennyVery Tough 1811 Capped Bust Half Ngc Vf-25 O-107 R.4! Looks Slightly Off-center!99 Cent Auction! 2004-d Wisconsin Low Leaf Error State Quarter Coin-no Reserve!1955 Double Die Lincoln Cent: Georgeous Look-mostly Red-bold Full Strike-choice+1998 1 Lincoln Cent On 1998 Roosevelt Dime Double Denomination Error Ngc Ms-67No Date Pcgs Ms64rd Reverse Die Cap Lincoln Memorial Cent Mint Error1864-l 1c Pcgs Ms64rb Rpd Fs-2302 S-3 (fs-006.71) Indian Penny1918/7 D Overdate Key Error Buffalo Nickel 5c Ultra Rare! Choice Fine! Gncoin2008 Monroe $1– Missing Edge Lettering Pcgs Ms-65 1980 1¢ Cupped Off-center Strike 1875 10¢ Struck 10% Off-center Pcgs 1885 Indian Head Double Die Bronze Cent1982-d 1¢ Triple Struck 1990 Kennedy Half Dollar - Off Center1976 Ike $1 Nice Double Clip Planchet 1982 1¢ Double Struck Us Coin Error No Collar When Struck 1934-p Bu Lincoln Wheat Cent Us Mint Error !1972 Double Die Obv. Lincoln Cent, Ngc Ms65 Rb. High Grade Rare Beauty2007 John Adams Presidential Dollar Missing Edge Lettering - Ngc Ms65 Mint Error2007 $1 Madison Missing Edge Lettering Pcgs Sp-64 2007 Washington Presidential Dollar Missing Edge Lettering - Ngc Ms66 Mint Error1981-d 1¢ Double Struck 2007 -s George Washington Proof Dollar Rare Waffle Cancelled U.s. Mint Error1955/55 Ddo Lincoln Cent Wheat Penny, Highly Pursued Mint Error! Excellent Shape1981 Wash. 25¢ Struck On Nickel Plan. Pcgs Ms-63 1979-d 25¢ “strong Clashed Dies Obv/rev” 2009 Wm. Harrison $1– Missing Edge Lettering Pcgs Ms-64 1983-p 50¢ - Strong Die Clash Obv. Ms-66 1964-d 1¢ Nice Double Struck 1999-d 5¢ Dramatic Lamination & Defective Plan Penny Roll #5 { 1955 Double Die Lincoln Wheat Cent & 1933-d Wheat Cent }1942/1 Mercury Dime Error, Overdate, Nice Rare Piece, Neat Coin Nice Detail N1021972-d $1 Nice Mis-align Obverse Die 2009 Sac $1 Missing Edge Lettering Pcgs Ms-66 2008 $1 Jackson Missing Edge Lettering Pcgs Sp-65 2009 Sac $1 Missing Edge Lettering Pcgs Ms-63 Ngc Ms 66 George Washington $1 *mint Error*~missing Edge Lettering~2007 Dollar2009 Z. Taylor $1 Missing Edge Lettering Pcgs Ms-632009 Wm. Harrison $1– Missing Edge Lettering Pcgs Ms-631999 - Double Struck + Die Clash Lincoln Cent Error Combined Ship #7861888-o Scarface Eds * Pcgs Ms63 * Silver Morgan Dollar * Vam 1b1 Usa Mint ErrorError-1944 Wheat Linc. 1c Massive Cud (broken Die)2008 $1 J.q. Adams Missing Edge Lettering Pcgs Sp-65 1976-d Ike $1 Tilted Partial Collar Strike 13. A No Date Jefferson Nickel Struck On Wrong Metal Lincoln Cent2010 $1 Pierce Missing Edge Lettering Pcgs Ms-64 2009 Polk $1 Missing Edge Lettering Pcgs Ms-64