The Altered Coin Threat
Altered coins start as genuine coins modified to resemble rare dates or varieties. They pass basic authentication since the base metal is real.
Altered Dates
Common examples: 1914-D cent from 1944-D, 1909-S VDB from 1909-S with added VDB, 1877 Indian Head from 1879.
Detection: Altered digits show tool marks, uneven surfaces, or different depth. Die diagnostics won't match known genuine dies. The area around altered digits shows disturbance.
Added Mint Marks
A mint mark added to transform a common coin into a scarce branch mint issue (e.g., adding CC to a Morgan dollar).
Detection: Wrong position, size, or angle. Surface disturbance around the mint mark. Wrong font style for that year.
Tooled Coins
Re-engraving details, smoothing scratches, whizzing (wire-brushing for fake luster), or plugging holes.
Detection: Unnatural metal flow, inconsistent surface texture, too-sharp details for the wear level. Magnification essential — most tooling invisible to naked eye.
Protection
- For key dates, always buy certified (PCGS, NGC, CAC).
- Study die diagnostics for specific dates you collect.
- Buy from reputable dealers at coin shows.
Up Next
This guide is for educational purposes. Where official standards, grading services, organization memberships, or legal requirements apply, consult the primary authority named in the references below or the relevant government agency.
Reviewed on February 4, 2026 by the US Coin Shows editorial team. Editorial policy
Official references and further reading
Frequently Asked Questions
What is an altered coin?
A genuine coin physically modified to appear more valuable — changed dates, added mint marks, re-engraved details, or smoothed damage.
How can I tell if a mint mark was added?
Check position, size, angle, and font against known genuine examples. Look for surface disturbance around the mint mark area under magnification.
Apply what you've learned