Cud (CUD)
A cud is a raised, blank area on a coin caused by a piece of the die breaking away at the rim. Error-Ref's definition is a die break that involves the rim and at least a little of the field or design beside it; Cuds on Coins calls it a marginal die break. When the piece falls out, the corresponding area on struck coins has no design impressed into it, leaving a featureless lump of metal joined to the rim.
How Does It Happen?
Coin dies endure enormous stress during the minting process. The U.S. Mint's circulating-coin presses apply roughly 35 to 100 metric tons of force per strike, depending on the denomination, and the Mint gives an average life of about one million strikes for a cent die and about 275,000 for a dime die. Error-Ref attributes most cuds to spontaneous brittle failure of the die steel; a small minority come from impacts.
A cud often follows this progression:
- Die cracks form: Hairline fractures develop in the die face from the constant striking pressure
- Cracks extend to the rim: The cracks propagate outward toward the edge of the die
- Die fragment separates: A section of die face between the crack and the rim breaks away completely
- Cud appears on coins: With that section of die missing, struck coins have an unstruck area — the cud — where the broken piece was
Some cuds stay the same size and shape for the rest of the die's life; others grow as more steel breaks away.
How to Identify a Cud
Cuds have distinctive characteristics that set them apart from other die damage errors:
- Location: Always joined to the rim, and reaching at least a little into the field or design. A raised blank area in the interior of the coin, not touching the rim, is an interior die break. A raised interruption that stays within the rim and follows its curve is a rim cud.
- Texture: The cud area is typically smooth or slightly rough — it lacks any design detail because that section of the die was missing when the coin was struck.
- Elevation: Cuds are raised above the coin's field because metal flows into the void left by the missing die fragment.
- Sharp boundary: The edge of the cud where it meets the normal design often shows a clear demarcation line corresponding to the original die crack.
- Opposite side: Unless the cud is very small, the area directly across from it on the other face is usually weakly struck or slightly sunken. Metal flows into the void in the broken die and pulls back from the intact die opposite, and with nothing pressing from the cud side, that area is struck with less force. Collectors use this weakness as one sign of a genuine break.
Cud vs. Similar Errors
| Error Type | Key Difference |
|---|---|
| Die crack | A raised line on the coin's surface — the die is cracked but no piece has fallen off yet |
| Pre-cud | A rim-to-rim die crack enclosing a section at the edge. Nothing has broken free or moved; the design is normal on both sides of the crack. See Pre-Cud |
| Retained cud | The piece has broken free but is held in place, usually by the collar. Its design is still there, raised as a plateau or offset from the design beside it. See Retained Cud |
| Interior die break | A die fragment has broken away from the die's interior, not connected to the rim |
| Rim cud | Not a small cud. The die loses part of its rim gutter, so the coin shows a raised interruption in the rim that follows the rim's curve, with no blank area reaching into the field. See Rim Cud |
Notable Examples
Large Cents (1793-1857)
Cuds are known on the early U.S. copper large cents, whose dies were often kept in service as they cracked and broke, and on 19th-century pieces generally; Error-Ref illustrates one on an 1863 Civil War store card.
State Quarter Cuds
The 50 State Quarters Program (1999-2008) produced billions of coins per year, and cuds appeared on many different dates and mint marks. The high production volume made cuds from this series relatively accessible to collectors.
Modern Shield Cents
Even with modern die technology, cuds continue to appear, and new ones are still reported on Shield Lincoln cents (2010-present).
Collecting Tips
- Size and location: Cuds range from small rim breaks to breaks that reach well into the design and cover the date, mint mark or part of a portrait. Note the size and position when you attribute one.
- Die state progression: Some collectors look for the same die as a pre-cud, a retained cud and a cud. Not every die passes through every stage.
- Cuds on Coins: The website cuds-on-coins.com maintains a registry of known cuds with its own numbering system, and the NumisDex catalog includes many of these documented varieties.
- A good first error: Cuds on Lincoln cents, Jefferson nickels and Roosevelt dimes turn up in circulation and are easy to recognize, which makes them a common starting point for new error collectors.