How can I tell if a coin is an error?
Visual Inspection
Start by examining the coin under good lighting with a magnifying glass or jeweler's loupe. Check for anything that looks out of place: off-center designs, extra letters, missing elements, or a different color than normal.
Rotate the coin and tilt it to catch reflections. Doubled dies often show a clear split in the lettering or numbers, especially on the date and mint mark.
- Off-center: design shifted to one side, with a blank crescent.
- Doubled die: clear doubling on letters, numbers, or design elements.
- Wrong planchet: wrong color, weight, or magnetic properties.
- Broadstruck: design stretched to the edge, no rim.
Tools and References
A coin catalog like the Red Book or online resources such as PCGS CoinFacts can help you compare your coin to known errors. A digital scale and calipers can check weight and diameter against standard specs.
If you suspect an error, avoid cleaning it. Cleaning can reduce value. Instead, place it in a protective holder and consider having it authenticated by a grading service like PCGS or NGC.
Common mistakes
- Cleaning a coin to see it better; cleaning damages the surface and lowers value.
- Relying on a quick glance; many errors require magnification to confirm.
- Assuming any anomaly is an error without checking standard references.
