If you’re just getting started with high-grade US coin collecting, the prevalence of counterfeits can be intimidating. Fortunately, there are many easy ways to detect counterfeits if you know what to look for.
Firstly, if you have a recent edition of the Red Book, you’ll have most of the information you need to spot counterfeit coins. Not only is this book an authoritative price guide on practically every US coin, but it also contains specifications for the coins’ designs. The US Mint has traditionally maintained very strict specifications for the weight, size, and design of coinage – and these are all areas where counterfeiters make mistakes.
A jeweler’s scale accurate to a tenth of a gram is a great tool for catching counterfeit coins. Most counterfeiters will use different metals from the ones in the original coin, giving the coin a different density and weight. If the coin in question deviates more than 1% from the known weight standard for that coin, it’s probably counterfeit.
Similarly, a caliper accurate to 1/100 of an inch can catch counterfeits that don’t have the official diameter of the original coin. If you’re an experienced collector, high-powered magnification is another great way to detect fake coins. Look for things like a bubbled surface, plating seams, file marks, and other imperfections. Once you know what to look for, detecting counterfeit coins can be as simple as running a few checks.