Coin Error Glossary: Definitions of Every Major Error Term
Coin error collecting has its own specialized vocabulary. Understanding these terms is essential for communicating with other collectors, reading reference materials, and accurately describing your finds. This glossary covers the major terms used in error coin collecting, from common types to technical manufacturing terms.
What This Means
Error coin terminology comes from the intersection of numismatics (coin collecting) and manufacturing (coin production). Many terms describe specific production failures, while others describe the physical characteristics of error coins. Learning this vocabulary helps you participate in the error coin community, understand listings and auction descriptions, and accurately identify your own finds.
What to Look For
- Broadstrike: A coin struck without the collar die, expanding beyond normal diameter
- Brockage: A coin with one normal side and one incuse mirror-image side from a stuck coin
- Clipped planchet: A coin with a missing portion of metal from a punching overlap
- Cud: A raised lump at the rim caused by a piece of the die breaking away
- Doubled die: A die that received multiple hub impressions at different angles
- Die crack: A raised line on the coin from a crack in the die surface
- Lamination: A planchet defect where metal separates into layers
- Machine doubling: Flat, shelf-like displacement from die bounce (less valuable than doubled dies)
- Off-center: A coin not properly centered between the dies during striking
- Struck through: A coin with an impression from debris caught between die and planchet
- Wrong planchet: A coin struck on a blank intended for a different denomination
Common Mistakes to Avoid
- Using "double die" instead of "doubled die" — the correct term is "doubled die" (past tense)
- Confusing "broadstrike" with "broadstruck" — both are used, but "broadstrike" is the error type
- Calling all doubling a "doubled die" — machine doubling and die deterioration doubling are different
- Using "misprint" for coins — misprints apply to paper money; coins have "errors" or "varieties"
- Not distinguishing between error (unintentional) and variety (intentional design variation)
What Affects Value
Knowing the correct terminology helps you price and sell error coins effectively. Accurate descriptions using proper terms build buyer confidence. Misusing terminology can lead to miscommunication and pricing errors. The glossary terms above represent the core vocabulary every error coin collector should know.
Upload a photo of your coin or currency and let ErrorHunt's AI scanner check for errors in seconds.
Scan NowFrequently Asked Questions
What is the difference between an error and a variety?
An error is an unintentional manufacturing defect (like an off-center strike). A variety is a recognizable die characteristic that may be unintentional (like a doubled die) or intentional (like a design change). The terms overlap in casual use.
Why is it "doubled die" and not "double die"?
The correct term is "doubled die" because it refers to a die that was doubled during the hubbing process. The die received multiple impressions, making it a "doubled" die. "Double die" is a common misnomer.
What does PMD mean?
PMD stands for Post-Mint Damage — any damage or alteration that occurred after the coin left the mint. PMD is not collectible as an error because it did not happen during production.
What is the Blakesley effect?
The Blakesley effect is a characteristic weakness in the rim opposite a clip on a clipped planchet. It occurs because the missing metal reduces striking pressure at the opposite point. Its presence helps authenticate genuine clips.