How to Spot Counterfeit Coins

Counterfeit coins are common, from fake silver dollars and gold coins to altered dates that turn an ordinary coin into an apparent rarity. This guide is for collectors and casual buyers at estate sales, flea markets and auctions. You will learn simple checks that catch many fakes and when to rely on professional authentication.

Know what gets faked

Counterfeiters focus on coins that are popular, valuable or easy to sell. Be especially careful with:

• Morgan and Peace silver dollars and Trade dollars.
• US and foreign gold coins of all kinds.
• Key dates and rare mint marks in popular series.
• Modern bullion coins and bars.
• Ancient and world coins sold as souvenirs.

Besides outright copies, watch for altered coins, where a real coin's date or mint mark has been changed or added to imitate a rarer one.

Start with weight and size

Every regular-issue coin has official specifications for weight, diameter and thickness. These are published in standard coin reference books and by mints. A digital scale that reads to at least a tenth of a gram, and ideally a hundredth, plus an inexpensive caliper, will catch many fakes.

Weigh the coin and measure it. A coin that is clearly off on weight or size is a strong warning sign. Allow for some small variation in worn coins. Keep in mind that skilled counterfeits can come close to the correct weight, so passing this check does not prove a coin is genuine.

Use a magnet

Silver, gold and copper are not magnetic. A coin that sticks to a strong magnet contains iron or steel and is not a genuine precious metal coin. (The 1943 steel cent is a real exception; it is supposed to be magnetic.) Like the scale, a magnet can rule a coin out but cannot prove it is real.

Look closely at details

Use a 5x to 10x loupe and compare the coin with photos of certified genuine examples of the same date and type.

• Soft or mushy details: Cast copies often look blurry, especially in fine areas like hair, feathers and lettering.
• Surface texture: Tiny pits, bubbles or a grainy, sandy look can indicate casting.
• Wrong look for its grade: A coin may show heavy wear in some places but sharp details elsewhere where wear would be expected.
• Repeated marks: Many counterfeits are made from the same false dies, so identical marks may show up on different fakes.
• Odd color or luster: Overly shiny, greasy or uniformly gray surfaces can be a sign of a fake or a plated base metal.

Check the edge and the date area

Examine the edge. Look for a seam line, which can show where two halves were joined, and check that reeding (the ridges on the edge) is even and matches genuine examples. Lettered edges should be crisp and correct.

For altered coins, study the date and mint mark area under magnification. Look for tool marks, scratches or discoloration around the digits, and compare the shape and position of numbers to known genuine pieces. Added mint marks may sit slightly wrong or show a seam around them.

Be wary of the deal and the story

Many counterfeit purchases come from situations that feel exciting. Red flags include:

• Prices far below what established dealers charge.
• Many identical "rare" coins offered by one seller.
• Pressure to decide quickly.
• Stories about coins found in a grandparent's attic that you cannot verify.
• Slabbed coins in holders from unfamiliar grading companies. Fake holders of well-known services also exist, so check the certification number on the grading company's own website.

Protect yourself when buying

For valuable coins, buy from established dealers who guarantee authenticity in writing, or buy coins certified by a major independent grading service and verify the certification number. Ask about return policies before you buy. If you are bidding at an auction, read the terms about authenticity and returns, and ask the auction company for a condition report or extra photos.

When to get help

If a coin passes your basic checks but something still feels off, show it to an experienced coin dealer or submit it to a reputable grading and authentication service. That cost is small compared to the price of a fake. If you discover you have been sold a counterfeit, keep all records and contact the seller, the venue, and if appropriate, law enforcement.

Quick checklist

• Know which coins are most often faked.
• Check weight, diameter and thickness against official specs.
• Use a magnet, then a loupe.
• Compare details, edges and dates with certified examples.
• Treat bargain prices and pressure as warning signs.
• Buy valuable coins with written guarantees or verified certification.