How to tell a fake coin from a genuine one

Fakes fall into two groups: modern copies made to deceive collectors, and older restrikes minted officially but later and from a different die. The difference matters: a restrike can be a genuine coin, a copy never is.

Five checks before buying

• Weight. Compare with the reference weight first. A deviation over 0.2 g for small denominations and 0.5 g for large ones is a warning sign.
• Diameter and thickness. Copies are often thicker: casting cannot reproduce the geometry.
• Edge. Lettering, reeding and edge patterns are the most expensive features to fake — check them first.
• Casting marks. Small pits, a wavy field and burrs along the rim are typical of cast copies.
• Magnet and sound. A copper-nickel coin should not stick to a strong magnet, and the ring of silver is hard to imitate.

What should raise suspicion

If the seller refuses to weigh the coin in front of you, the conversation is over: an honest seller has nothing to hide.

Check the patina separately. Artificial patina lies in an even layer, does not follow the relief and often leaves dark stains around letters. Genuine patina is uneven and follows the micro-relief of the field.

When expert opinion is required

For expensive pieces, do not save on expertise. A laboratory report on weight, metal composition and die links, together with a numbered certificate and photographs, protects the deal better than any promise.