Cud Errors: Die Breaks That Create Raised Blobs

A cud error appears as a raised, featureless lump of metal on the rim of a coin. It occurs when a piece of the coin die breaks away and falls out, leaving a void that fills with metal during striking. Cuds are one of the more visually distinctive mint errors and have a dedicated following among error collectors who catalog them by die, position, and size.

What Causes Cud Errors?

Coin dies are made of hardened steel, but they don't last forever. After striking millions of coins, dies develop stress fractures, especially around the rim where the metal is thinnest. When a piece of the die near the rim breaks off completely, the broken area leaves a cavity in the die face. During subsequent strikes, metal flows into this cavity and forms a raised, shapeless blob — the cud.

The key distinction is that the break must extend to the rim. A die break in the interior of the die that doesn't reach the rim is classified as a retained die break or interior die break, not a cud.

How to Identify Cud Errors

• Raised, featureless blob — the cud area is raised above the normal surface but shows no design detail
• Located at the rim — true cuds always touch or include the rim of the coin
• Irregular shape — cuds follow the outline of the broken die fragment, not any geometric shape
• Same metal as the coin — the cud is integral to the coin, not an attachment or adhesion
• May appear on obverse or reverse — cuds can occur on either die

Cud vs. Die Crack vs. Die Break

These three error types are related but distinct:

• Die crack: A thin raised line on the coin surface from a crack in the die — no metal is missing from the die
• Die break: A larger area where die metal has separated, creating a raised area on the coin — may be interior
• Cud: A die break specifically at the rim where a piece of the die has fallen away completely

What Affects Cud Error Values

• Size — larger cuds are scarcer and more visually impressive
• Location — cuds that obscure key design elements or lettering are often more interesting to collectors
• Denomination and date — cuds on scarcer denominations or older dates may carry higher premiums
• Condition — well-preserved surfaces around the cud add value

Finding and Scanning Cuds

Cuds are one of the easier errors to spot because the raised blob is visible to the naked eye. ErrorHunt's AI scanner can help confirm whether a raised area on your coin is a genuine cud error or another type of defect. Photograph the coin with good lighting to clearly show the raised area.