Identification Guides
Working out what you have. Doubled dies, repunched mintmarks, die clashes, and the look-alikes that are not errors at all.
64 articles
Brockages: Why One Side Is Sunk In and Backwards
This Civil War token reads STAND BY THE FLAG. Turn it over and the same design is there again, but pressed into the metal and backwards. It's a brockage, and it's one of the easiest errors to understand once you've seen a clear one. An 1863 Stand By The Flag token (Fuld 213): the normal side, and th
Woodies: Why Some Old Pennies Look Like They're Made of Wood
Every so often an old Lincoln or Indian Head cent turns up with light and dark stripes running across it, like the grain in a piece of wood. Collectors call these woodies, and the stripes aren't toning or damage. They're a mistake in the metal itself. A 1915 Lincoln cent woodie: light and dark bands
The 1943 Penny: America's Most Famous Mistake (and the One That Happened Backwards)
You've probably heard that you should check your 1943 pennies. Here's the real reason — and it's stranger than the rumor. Why 1943 Was Different Copper was a war metal in 1943 — needed for shell casings and wire — so for one year the U.S. Mint struck the Lincoln cent in zinc-coated steel. More than
Die Clash Overlays: Where Clash Marks Appear on 385 Designs
We have published 385 die clash overlays, covering 32 series from half cents to gold double eagles. Each one shows where clash marks fall on that design. They are collected in one place: Die Clash Overlays.What a Die Clash IsWhen a planchet fails to feed between the dies, the obverse and reverse die
"L on the Rim" Is Almost Never an Error. But There Is a Real One.
The BeliefLook at enough Lincoln cents and you will find one where the L of LIBERTY appears to touch the rim, merge with it, or sit on it. Search for it and you will find them listed for sale constantly, and at least one widely shared how-to article treats it as a genuine rim error.It is almost neve
Not in the Books #23: An 1863 Indian Head With Three Errors
all three errors are visible on the obverse Three at Once Most error coins carry one error. This 1863 Indian Head cent carries three, on the same planchet. Multiple die clashes. The obverse and reverse dies struck each other without a planchet between them, more than once. The wreath from the revers
Trail Dies: Catalogued as a Doubled Die for Six Years
annotated with arrows pointing at the trails. An Attribution That Took Six Years to Correct In late 1994 John Wexler received a Lincoln cent from G. J. Lawson showing a strange bending in the steps of the Memorial, beneath the columns. He examined it and concluded that the fluting lines from the col
Spiked Heads: When the Portrait Grows a Horn
A Die Crack With a Memorable Shape A spiked head is a die crack that runs from the rim into the portrait and produces a raised spike — a thorn, a horn, a spear — projecting off the head of whoever is on the coin. The mechanism is ordinary die failure. Under repeated striking, a crack start
Split Dies: When the Die Comes Apart
A Crack, a Cud, and a Die in Two Pieces A die crack is a hairline. A cud is a bite out of the rim. A split die is the die coming apart in the press and striking coins anyway. This is the terminal stage of die failure. The crack does not stop partway across the face — it runs rim to rim, cu
Overdates: When Yesterday's Date Won't Let Go
Two Dates on One Coin An overdate is a coin where a new date has been punched over an existing date on a working die. The old date's remnants — curved lines, bases, serifs of the previous digit — remain visible underneath or beside the new date. The result is a coin that shows two dates at
Capped Die Errors: When a Coin Refuses to Leave the Press
Every Coin Is Supposed to Leave A coin press operates hundreds of times per minute. The upper die (hammer die) descends, strikes the planchet against the lower die (anvil die), then retracts. The finished coin is ejected, and the next blank feeds in. The entire cycle takes a fraction of a
Broadstrike Errors: When the Collar Fails
The Third Die You Never Think About Every coin struck at the U.S. Mint is formed by three components, not two. The obverse die presses the front. The reverse die presses the back. And the collar — a metal ring surrounding the planchet — constrains the edge, shapes the rim, and holds the co
Die Clash Overlays for Indian Head Cents: Patterns and Notable Examples (1859–1909)
Die clashes occur when the obverse and reverse dies strike each other without a planchet between them, leaving impressions of the opposing die’s design elements on each die. When coins are subsequently struck from those clashed dies, faint mirror-image traces of the opposite side appear on the coin.
Wrong Planchet Errors: When a Coin Gets Struck on the Wrong Metal
When the Wrong Blank Ends Up in the Press The U.S. Mint produces billions of coins per year across multiple denominations, often running adjacent press lines in the same facility. Cent planchets, nickel planchets, dime planchets, quarter planchets — all moving through the same building, st
Die Clash Overlays for Flying Eagle Cents: Mule Die Clashes (1856–1858)
Die clashes occur when the obverse and reverse dies strike each other without a planchet between them, leaving impressions of the opposing die’s design elements on each die. When coins are subsequently struck from those clashed dies, faint mirror-image traces of the opposite side appear on the coin.
Strike Through Errors: When the Mint’s Factory Floor Leaves Its Mark
When Something Gets Between the Die and the Coin Every coin struck at the U.S. Mint follows the same basic process: a blank planchet is placed between two dies, and the dies close with 35 to 150 tons of force. The design transfers from the die face to the planchet in a fraction of a second
Die Clash Overlays for Large Cents: All Design Types (1793–1857)
Die clashes occur when the obverse and reverse dies strike each other without a planchet between them, leaving impressions of the opposing die's design elements on each die. When coins are subsequently struck from those clashed dies, faint mirror-image traces of the opposite side appear on the coin.
Off-Center Strikes — When Coins Miss Their Mark
When Coins Miss Their Mark Off-center strikes are among the most visually dramatic errors in U.S. coinage. They occur when a planchet (blank coin) is not properly centered between the dies before striking, resulting in a coin where the design is shifted to one side and part of the planchet
Over Mint Marks: When a Coin Was Meant for Another City
Before 1990, every working die used in U.S. coinage was manufactured at the Philadelphia Mint and then shipped to the branch mints (Denver, San Francisco, New Orleans, Carson City, West Point) for production. The mint mark -- that small letter identifying which facility struck the coin -- was added
Die Clash Overlays for Half Cents: All Design Types (1793–1857)
Die clashes occur when the obverse and reverse dies strike each other without a planchet between them, leaving impressions of the opposing die's design elements on each die. When coins are subsequently struck from those clashed dies, faint mirror-image traces of the opposite side appear on the coin.
Cherry-Picking Error Coins at Coin Shows: What to Bring and Where to Look
Where Knowledge Becomes Profit "Cherry-picking" is the practice of finding coins with unrecognized varieties, errors, or attributes in dealer inventories and purchasing them at generic prices. It's one of the most rewarding aspects of numismatics — combining knowledge, patience, and the thrill of di
How New Error and Variety Categories Get Discovered — The Process Behind Cataloging a New Die Variety
From "That Looks Weird" to a Catalog Number: The Variety Attribution Process Every cataloged die variety started the same way: someone noticed something unusual on a coin. But getting from "this looks different" to an officially recognized and numbered variety involves a structured process with mult
No Date on Your Buffalo Nickel? Read the Coin Before You Reach for Acid
A Buffalo nickel with no date isn't an error, and it isn't rare. Millions of them lost their dates in circulation. The good news is that the year is often still there to be read, if you know where to look, and acid is only one way to find it. The date sits on the Indian's shoulder, just above Fra...
Silver vs. Clad Coinage: How to Tell Pre-1965 from Later
Silver or Clad? The Edge Tells the Story In 1965, the U.S. Mint moved dimes and quarters from 90% silver to a copper-nickel clad composition, and half dollars to a 40% silver clad composition (copper-nickel clad from 1971). Knowing how to tell silver coins from clad is a fundamental skill — whether
San Francisco Proof vs. Business Strike: How to Tell the Difference
Proof Coins vs. Business Strikes Proof coins and business strikes (regular circulation coins) are made from the same designs but through fundamentally different manufacturing processes. Understanding the difference is important because proofs are struck specifically for collectors and carry differen
Vending Machine, Counting Machine, and Crimper Damage on Coins
Machine Damage That Looks Too Clean to Be Random Not all post-mint damage looks like random scratches and dings. Some damage is surprisingly clean, uniform, and repeatable — which makes collectors wonder if it might be a mint error rather than damage. Vending machines, coin counting machin
PMD Vocabulary: Scratches, Gouges, and Damage Every Collector Should Recognize
Understanding Post-Mint Damage (PMD) Post-mint damage is any alteration to a coin that happened after it left the Mint. Learning to recognize common types of PMD is essential because it's the most frequent cause of false "error" identifications. Knowing the vocabulary also helps you communicate clea
My Coin Looks Melted or Blobby — Die Error or Acid Damage?
When a Coin Looks "Melted" "My coin looks like it melted" is one of the most common descriptions posted by new collectors encountering unusual-looking coins. The features are soft, blobby, or indistinct — and the first instinct is that something dramatic happened. In reality, there are thr
Colorized, Toned, and Rainbow Coins: Error, Treatment, or Natural?
Why Is My Coin Colorful? Coins with unusual colors — rainbow hues, deep blues, vivid reds, or painted designs — generate a lot of questions. Is it an error? Is it valuable? Is it natural or artificial? The answer depends on what kind of color you're seeing and how it got there. There are t
Tall Rim or Thick Edge on Your Coin: Mint Error or Post-Mint Damage?
Understanding Rim Anomalies "My coin has a thicker rim than normal — is it an error?" This is a common question, and the answer depends on what's actually going on. Some rim anomalies are genuine mint errors worth a premium. Others are just post-mint damage. Telling them apart requires understanding
Mint Error vs. Post-Mint Damage: 5 Questions to Ask Before You Get Excited
Is It a Mint Error or Just Damage? You found something unusual on a coin. Maybe the lettering looks doubled, the rim is oddly shaped, or part of the design seems missing. Before you start calculating how much it's worth, you need to answer one fundamental question: did this happen at the M
Repunched Mint Marks (RPM): What They Are and How to Find One
Every Mint Mark Was Punched by Hand Before 1990, every mint mark on every United States coin was applied by hand. A Mint engraver took a small steel punch — a rod with a raised letter on its tip (D, S, O, W, or CC) — positioned it on the working die, and struck it with a hammer to impress
What Is a Mule Error? The 2000 Sacagawea/Quarter Mule Explained
Mule Errors: When the Mint Uses the Wrong Dies Together A mule error occurs when a coin is struck using two dies that were never intended to be paired together. Unlike wrong planchet errors (correct dies, wrong blank) or off-center strikes (correct dies and planchet, wrong alignment), a mu
Wrong Planchet Errors: How to Tell If Your Coin Is Struck on the Wrong Blank
Wrong Planchet Errors: Among the Most Dramatic Mint Errors A wrong planchet error (also called an off-metal error) occurs when a coin is struck on a planchet intended for a different denomination — or in rare cases, on a foreign planchet that found its way into the coining press. The resul
Lamination Error vs. Environmental Damage: How to Tell
Peeling Metal: Lamination Error or Environmental Damage? When you find a coin with metal that appears to be peeling, flaking, or separating into layers, you're looking at one of two things: a genuine lamination error (a mint-made planchet defect) or environmental damage (post-mint corrosio
What Is a BIE Error on a Lincoln Cent, and Is It Worth Anything?
The BIE Error: A Beginner-Friendly Variety If you've been searching through Lincoln cents and found what looks like an extra letter "I" between the B and E of LIBERTY, congratulations — you may have found a BIE error. These are one of the most popular die varieties among beginning collecto
Struck-Through Errors: How to Tell a Grease Fill from Damage
Struck-Through Errors: Grease, Foreign Objects, and How to Tell A struck-through error occurs when something gets between the die and the planchet during striking. The foreign material prevents part of the design from being fully impressed into the coin, creating a distinctive area of miss
Broadstrike vs. Off-Center Strike: What Is the Difference?
Broadstrike vs. Off-Center: Two Strike Errors, Two Different Causes Broadstrikes and off-center strikes are both caused by problems during the striking process, but they result from different mechanical failures. Understanding the distinction helps with attribution, value assessment, and k
Off-Center Strike vs. Clipped Planchet: How to Tell the Difference
Two Common Errors That Look Similar at First Glance Off-center strikes and clipped planchets are two of the most frequently encountered mint errors, and new collectors sometimes confuse the two. Both result in coins with incomplete designs, but they have fundamentally different causes — an
Die Crack vs. Die Chip vs. Cud: How to Tell Them Apart
Understanding Die Damage: Cracks, Chips, and Cuds As U.S. Mint dies wear down from striking thousands of coins, they develop damage that transfers to every coin they strike. Three of the most common types of die damage are die cracks, die chips, and cuds. While they're all caused by deteri
1995 Doubled Die Cent: How to Confirm the Doubling on LIBERTY
The 1995 DDO: A Modern Classic Found in Circulation The 1995 Doubled Die Obverse is one of the most significant modern-era Lincoln cent varieties. Unlike older doubled dies that are primarily found in collections, the 1995 DDO was discovered while coins were still actively circulating — an
Is Your 1972 Cent a Real Doubled Die? How to Check the Obverse
The 1972 Doubled Die Obverse: A Popular and Affordable Classic The 1972 DDO is one of the strongest doubled dies in the Lincoln cent series and one of the most popular varieties among collectors. Unlike the 1955 and 1969-S doubled dies that command five-figure prices, the 1972 DDO remains
1969-S Doubled Die Obverse: How to Identify vs. Worthless Look-Alikes
The 1969-S DDO: One of the Rarest Lincoln Cent Errors The 1969-S Doubled Die Obverse is one of the most dramatic and valuable Lincoln cent errors ever produced. With values exceeding $60,000 in Mint State, it rivals the famous 1955 DDO in both visual impact and collector demand. But for ev
Split Planchets: When a Coin Breaks in Half (And Why the Other Half Might Be Out There)
Every coin is a sandwich. Metal layers bonded together, rolled thin, punched into blanks, and struck under enormous pressure. Most of the time, the metal holds. But sometimes there's a flaw hiding inside -- a gas bubble from the casting process, a slag inclusion, contamination from the rol
Counter Clashes: What Happens When a Die Clash Clashes Back
If you've read our [ Die Clashes: Ghost Images From Empty Strikes ] ( https://www.numisdex.community/forum/error-die-clashes/die-clashes-ghost-images-from-empty-strikes ), you know the basics: two dies strike each other with no coin between them, and ghost images of each side's design tran
When a Die Dies: How Cuds Form and Why Every Stage of Failure Is Collectible
Every coin you've ever held was made by two dies -- an obverse die and a reverse die -- slamming together under 35 to 150 tons of force. A single die might strike 200,000 to 500,000 coins before it's retired. But some dies don't make it that far. They break.When a piece of the die breaks away at the
Not All Doubled Dies Are Created Equal: The Three Levels of Doubling Most Collectors Don't Know About
When most collectors hear "doubled die," they picture the famous 1955 Lincoln cent with its dramatic, naked-eye doubling on LIBERTY and IN GOD WE TRUST. But here's something most people don't realize: not all doubled dies come from the same place. Strong doubling — unmistakable to the nake
What Is a Die Clash? One of the Most Common and Most Misunderstood Mint Errors
Most coins you've held were struck by two dies -- one for the obverse, one for the reverse -- slamming together at 35 to 150 tons of force. Now imagine what happens when the machine fires... but no coin blank is between them. A die clash in action — ghost design elements from the reverse d
VAM Collecting: The Morgan Dollar Deep Dive
Thousands of Die Varieties, One System to Catalog Them All Most error collecting asks one question: is this coin interesting? VAM collecting asks a harder one — which specific die pair struck this coin? VAM stands for Van Allen-Mallis, after Leroy C. Van Allen and A. George Mallis, who bui
UFOs: Coin Mysteries Waiting to Be Solved
The Error Types That Defy Classification An Unidentified Fascinating Oddity (UFO) is a die variety that doesn't fit into any established error category. Raised bumps, unexplained marks, unusual impressions — features that reproduce consistently on every coin from that die, confirming they'
Transitional Errors: When Old Meets New at the Mint
Coins From the Design Changeover Window A transitional error occurs when the Mint pairs a die from one design type or year with a die from another. These happen during the narrow window when an outgoing design is being retired and a new one is being introduced — both sets of dies coexist i
Trail Dies: The Affordable Alternative to Doubled Dies
Tendrils From a Polishing WheelA trail die variety shows raised tendrils extending from the corners of letters, numbers, and design elements — thin lines that gradually narrow and fade into the field. They're caused by careless die polishing: when rotary polishing tools contact the die, soft fibers
Collar Errors: The Overlooked Third Die
Everyone Forgets About the Collar Most collectors think of coin production as two dies — obverse and reverse. But there's a third die that's just as important: the collar . This steel ring surrounds the planchet during striking, constrains the expanding metal, forms the coin's precise diam
Broadstrikes: Full Design, No Collar
Bigger Than Normal A broadstrike happens when a coin is struck without the restraining collar die — the steel ring that normally gives a coin its precise diameter and edge detail. Without that collar, the planchet metal flows outward under 35-150 tons of force, producing a coin that's noti
Off-Center Strikes: The Sweet Spot at 50%
When Coins Miss Their Mark An off-center strike occurs when a planchet isn't properly seated between the dies at the moment of striking. The result: a coin with the design on only a portion of the surface, leaving the rest blank. The displacement can range from a barely noticeable 5% to a
Wrong Planchet Errors: When a Coin Gets the Wrong Body
The Right Design on the Wrong Metal A wrong planchet error is among the most dramatic and valuable error types in numismatics. It happens when a coin is struck on a planchet intended for a different denomination — or even a different country's coinage. The die design is correct, but the si
Repunched Mint Marks: Hand-Punched History
When a Mint Employee's Mallet Struck Twice Before 1990, the U.S. Mint added mint marks to working dies by hand . A Mint employee would position a small steel punch bearing the appropriate letter (D, S, O, CC, W) over the designated spot on the die and strike it with a mallet. This manual p
Die Clashes: Ghost Images From Empty Strikes
When Dies Strike Each Other A die clash happens when the obverse and reverse dies slam together without a planchet between them . At 750-850 coins per minute, the automated feed system occasionally fails to deliver a blank — but the press cycle doesn't stop. The dies close at full force (3
Cuds: When Dies Break at the Rim
The Life Cycle of a Dying Die A cud is a raised, blank area on a coin caused by a piece of the die breaking away at or near the rim. It's the final stage in a die's battle with metal fatigue — and every cud tells the story of a die that literally fell apart under pressure. The progression
The Most Famous Doubled Die: 1955 Lincoln Cent DDO
The Error That Started It All The 1955 Lincoln Cent Doubled Die Obverse is the most famous error coin in American numismatics. The doubling is so dramatic it's visible to the naked eye — LIBERTY, IN GOD WE TRUST, and the date all show extreme separation between two fully formed images. An
How to Tell Real Errors From Post-Mint Damage
The #1 Skill Every Error Collector Needs The single most important skill in error coin collecting is distinguishing genuine Mint errors from post-mint damage (PMD) . A coin that was dropped, scratched, or tumbled in a dryer can superficially resemble an error — but the difference in value
Top 10 Most Popular Lincoln Cent Errors
Top 10 Most Popular Lincoln Cent Errors Published May 5, 2026. Mintages and counts of known examples are as reported at the time by the sources named below; this article gives no prices. The Lincoln Cent, minted since 1909, is one of the most widely collected U.S. coin series. Its long production hi
Die Varieties vs. Die Errors: What's the Difference?
Die Varieties vs. Die Errors: What's the Difference? In numismatics, "variety" and "error" are often used interchangeably, but they refer to distinct categories of coins that deviate from the norm. Understanding the difference helps you identify what you have, communicate accurately with other colle
How to Identify a Doubled Die
How to Identify a Doubled Die PennyDoubled dies are one of the best-known die varieties in U.S. numismatics. From the famous 1955 Doubled Die Lincoln Cent to modern discoveries, learning to identify doubled dies is an essential skill for any variety collector. True doubled die (left) vs. machine dou