This page discusses the basics of detecting forgeries. For a more complete discussion, see Ancient Coins & Modern Fakes or Fakes.

This page deals primarily with coins sold by dealers and ancient coin collectors. Coins sold by anyone else (e. g., near a tourist site) are most likely to be fake, and should never be purchased unless you have much experience with ancient coins.

The primary types of fakes, according to method of production, are as follows:

• Cast copies: These are made by making a mold from an authentic coin, and then pouring metal into the mold, one half at a time.
• Electrotype copies: These are made by electrolysis and filling.
• Struck from new dies: Made the old fashioned way, with a hammer. Often these coins are offered for sale as copies, but unscrupulous or unknowledgeable sellers may attempt to pass them off as authentic.
• Altered real coin: An inscription might be changed to make it appear to be a more valuable coin. If detail is added to a coin (e. g., hairlines added back in to make it look to be in better condition that it is), it is referred to as "tooled."

So this is sounding bad for buying authentic coins? Well, yes and no. The good news is that few ancient coin dealers sell fakes, and usually they won't be in business for very long if their reputation is tarnished. So if you buy from a dealer that has been in business for a long time, you risk is quite low, and the dealer may offer a lifetime guarantee of authenticity.

But it still pays to have a little knowledge of fake detection method, so I'll give a short introduction here.

Most cast or electrotype fakes will show a seam running around the entire coin on the edge, similar to the seam on a cast plastic part, such as you would find on a piece for a model car. If a straight line is seen on the edge, assume the coin is fake.

But fakers will try to hide this line by filing it off. Most ancient coins have a ragged or at least irregular "flan" (the disk of metal a coin is struck on). Small or large cracks in the edge of a coin are common. Imagine a coin made out of dough that almost fills the dies. It would have folds and cracks on the edge, like an ancient coin has. If you see a coin that has an edge section that is perfectly flat, it has probably been filed to hide the seam line, and is fake. Also look for a series of file marks.

Note that to inspect the edge of an ancient coin, it may be necessary to remove it from its holder. This makes coins sold in stapled cardboard holders a bit annoying. Don't be afraid to ask to remove the coin for inspection.

Fakes will often show a rough surface on both sides. But authentic ancient coins often have surface porousity as well. Being able to tell the difference takes some experience with both real and fake ancient coins. A warning sign is if the more worn portions of the coin have as much roughness as protected or less worn areas.

One final note about detecting fakes. How would you know a real coin from a fake one, if you've never seen the real one? You will learn much about determining authenticity of ancient coins by viewing as many as you can, primarily in person. So try to find ancients at coin shows, or look at someone's collection. The more you see the real thing, the more the fake will stand out.

Continue to Identifying Ancient Roman Coins.

If you have any questions or comments, please send e-mail to me at .

Last updated January 27, 2001.
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