How a die fails
Dies are hardened steel under enormous repeated stress. Late in a die's life, or early if the steel was flawed, a fracture begins. It shows on coins as a fine raised line: a die crack. As the crack propagates, small pieces of die surface beside it can break away, leaving a small void that fills with metal at each strike and shows as a raised blob: a die chip. If a crack reaches from the rim into the design and around back to the rim, the piece it encloses can break off entirely, and the coin shows a raised, featureless area where that piece of the die used to be: a cud. If the piece breaks but stays in place, held by the die collar or by friction, it strikes coins slightly out of position: a retained cud.
All of them are raised on the coin, because all of them are voids in the die that the planchet's metal flowed into. That single fact separates the whole family from damage.
How each looks
| Feature | Die crack | Die chip | Cud | ||
|---|---|---|---|---|---|
| Shape | Thin raised line | Small raised blob or lump | Raised featureless area | ||
| Location | Anywhere | often rim to design | Beside cracks | in recesses of design | Always touches the rim |
| Design under it | Intact, crack runs across it | Filled in where the chip is | Absent | replaced by blank raised metal | |
| Opposite side | Normal | Normal | Often weak in the corresponding area | ||
| Progression | Grows longer over die life | Grows as more breaks away | Terminal stage | ||
| Typical value | Minor unless large or dramatic | Minor unless large | Meaningful, scaled to size |
Size and location on the design set the value. A cud that removes the date or a major device is the collector's target.
Die crack in detail
A die crack is the most common die error and the least valuable. It is a fine raised line, rounded in profile, toned like the coin around it, running across design elements without disturbing them. It can be a hairline or a heavy ridge. On many dates, cracks are so routine that a coin without one is harder to find than one with. They are tracked by die-state specialists because their growth dates a coin within the die's life; die state progression covers that use. Dramatic cracks — long, heavy, branching, or in a striking position — have a small collector market. Most have none.
The look-alike is a scratch. A scratch is incuse; a crack is raised. A fingernail catches on a crack and slides through a scratch. Error vs damage covers the test.
Die chip in detail
A die chip is a small piece of die surface that broke away, leaving a void. On the coin it is a small raised lump, often in a recess of the design where the die's surface was thinnest — inside a letter, in the mint mark, between devices. Filled letters and filled mint marks from chips are very common. The look-alike is a struck-through grease filling, which is smooth and slightly recessed rather than raised; a chip stands proud of the design.
Chips are the most overpriced error in the online market, because a small raised lump inside a letter photographs dramatically and a listing can call it anything. Tiny die chip price hype is the site's warning on the subject. A chip is worth something only when it is large enough to be seen without magnification or sits somewhere that changes the design in a way collectors find interesting.
Cud in detail
A cud is the end of the process, and it is the member of the family with a real market. A piece of the die, bounded by a crack running from rim to rim, broke off. Every coin struck afterward shows a raised blob of blank metal in that area, because the planchet flowed up into the void with nothing to shape it. The design that used to be there is gone. The opposite side of the coin is often weak in the same area, because the metal went into the cud instead of into the opposite die's recesses.
Cuds are classified by size and by what they obliterate. A small rim cud that removes a few denticles is minor. A cud that takes the date, the mint mark, or a major portion of the portrait is significant. Cuds on scarce dates and on silver and gold are scarce because those dies were replaced before failing so completely. The retained cud, where the piece stayed in the die, shows a section of design displaced in height with a crack around it, and is collected alongside full cuds.
The look-alike is rim damage, which is flattened or incuse with displaced metal beside it and a normal opposite side. A cud is raised, featureless, and paired with opposite-side weakness.
Telling them apart in practice
- Is it raised? If not, it is damage, and none of the three.
- Is it a line, a lump, or an area? Line is a crack, lump is a chip, area is a cud or die break.
- Does the area touch the rim? Yes is a cud; no is an interior die break.
- Is the opposite side weak in the same place? Yes supports a cud.
- Is the raised area featureless or does it carry displaced design? Featureless is a full cud; displaced design with a crack around it is a retained cud.
Value and certification
Cracks and chips are rarely worth certifying; the fee usually exceeds the certified value unless the example is extreme. Cuds are certified routinely, with the label describing the location, and their sold prices scale with size and with what the cud removes. Search the denomination and date with the word cud, filter to sold, and compare examples of similar size. Error coin grading and certification covers submission; the doubled die hub covers the rest of the die-error family.
Certified cuds show what the market pays for; certified die cracks show how little it pays for minor ones. Both are worth studying.
Frequently asked questions
Is a die crack valuable?
Rarely. Die cracks are the most common die error and most are worth nothing extra. Long, heavy, or dramatically placed cracks have a small collector market.
What makes a cud a cud?
A raised, featureless area where a piece of the die broke off, and it must touch the rim. An interior break that does not reach the rim is a die break, not a cud.
Why is my filled letter not worth much?
Because a small die chip inside a letter is one of the most common errors that exists. It photographs well and sells poorly. Size and visibility without magnification are what create value.
What is a retained cud?
A cud where the broken piece of die stayed in place. The coin shows a section of design displaced in height, with a crack surrounding it.