Detecting Counterfeit & Altered Coins
Learn to protect yourself from fake and altered coins — identification techniques, testing methods, and when to call in the professionals.
8 parts · Free to read
The Counterfeit Coin Problem: Why Authentication Matters
The scope of the counterfeit coin problem, how it affects collectors, and why authentication is essential for valuable purchases.
Weight, Diameter & Specific Gravity Testing
The first line of defense — using precision scales, calipers, and specific gravity tests to quickly identify suspicious coins.
Identifying Cast Counterfeits vs. Die-Struck Fakes
How to tell cast counterfeits (with their telltale signs) from more dangerous die-struck fakes, and what to look for under magnification.
Altered Dates, Added Mint Marks & Tooled Coins
Detecting coins that started genuine but were altered to appear more valuable — re-engraved dates, added mint marks, and removed damage.
The Most Commonly Counterfeited US Coins
A visual guide to the US coins most frequently counterfeited — from 1909-S VDB cents to gold dollars — and specific diagnostics for each.
Chinese Counterfeits: What to Watch For
The modern wave of mass-produced counterfeits from China — how they're made, how they enter the market, and how to spot them.
Tools & Technology for Authentication at Home
Build your authentication toolkit — loupes, USB microscopes, precision scales, Fisch detectors, XRF analyzers, and smartphone apps.
When to Use a Professional Authentication Service
When DIY isn't enough — how PCGS, NGC, and ANACS authenticate coins, costs, turnaround times, and what happens if your coin is fake.
Ready to Find Your Next Show?
Browse hundreds of upcoming coin shows across every state, with dates, venues, and contact details.