How to spot a counterfeit coin: 6 checks

As coin values rise, so does the incentive to fake them — and modern counterfeits can be convincing. You don't need lab equipment to protect yourself, though. A handful of quick, physical checks will catch the large majority of fakes before money changes hands. Here are six to run before you buy, especially on anything valuable.

1. Weigh it

Genuine coins were struck to a precise standard weight for their type and era. Counterfeits, often made from the wrong alloy, frequently miss that weight — sometimes by a little, sometimes by a lot. A small, accurate scale that reads to a tenth of a gram is one of the cheapest and most powerful tools you can own. Look up the standard weight for the type, then compare. An off weight is a serious red flag.

2. Measure diameter and thickness

Fakes are often struck from improvised dies or cast in molds that don't quite match the genuine dimensions. A pair of calipers lets you check diameter and thickness against the known standard. Cast counterfeits in particular tend to be slightly thick or slightly large because of how the mold fills. Small deviations matter — genuine coins are remarkably consistent.

3. Test with a magnet

Most genuine silver and gold coins are non-magnetic. If a coin that should be precious metal sticks to a magnet, it's almost certainly fake. Treat this as a useful first screen, not a final verdict: a counterfeit made from a non-magnetic base metal will pass the magnet test happily. So a fail is damning, but a pass proves only that one thing. Always combine it with the weight and detail checks.

4. Inspect the edge

The edge tells you a lot. Many genuine coins have reeding (those fine vertical ridges) or edge lettering struck to a consistent pattern. On fakes, reeding can be uneven, mushy, or the wrong count, and a visible seam running around the edge is a classic sign of a cast counterfeit — genuine struck coins don't have a casting seam. Run the edge under magnification and feel for anything irregular.

5. Study the fine detail under magnification

• Sharpness: Genuine struck coins show crisp, fully formed detail. Cast fakes often look soft, rounded, or slightly blurry, as if the design melted a touch.
• Surface texture: Look for tiny pits or bubbles in the fields — a telltale sign of casting that you won't find on a struck coin.
• Repeated flaws: A raised lump or tooled spot in an odd place can mark where a mold defect or an altered detail sits.

6. Listen to the "ping"

An old but useful trick: balanced on a fingertip and tapped gently, a genuine silver coin gives a long, clear, high ring. Many base-metal fakes give a dull, short thud instead. It's a soft test, not proof, and it takes a trained ear — but combined with the others it adds one more data point. Never bang coins together to do this; tap lightly.

Putting the checks together

No single check is conclusive on its own — the magnet can be fooled, a clever fake can hit the right weight. The power is in stacking them: weight, dimensions, magnetism, edge, detail, and ring together catch the overwhelming majority of counterfeits. For high-value pieces where it still matters, professional authentication is the final word.

The app identifies likely type and variety and shows market reference range estimates — not appraisals, and not an authenticity guarantee. These six checks are your hands-on first line of defense before you ever trust a price.