How to Test Gold Coins

Look up the gold coin's specifications. All gold coins of the same year, type and denomination are made exactly the same way.

Measure the coin. The diameter should be exactly what is listed for that coin. If it is even 1 millimeter off, it is probably not genuine.

Weigh the coin on a very sensitive scale. This should ideally be a coin scale, but a jewelry scale or postage scale will do. Most fakes weigh less than genuine coins.

Closely examine the surface. Fake gold coins often appear too dull or too bright. Place it next to a gold coin you know is genuine. The color of a fake coin will be different. Counterfeit coins often lack detail and appear grainy since many are cast from molds of real coins. Examine the edge. If you see a seam, then it is probably two cast sides glued together.

Look through a magnifying glass at the coin's date and mint mark. These details are often altered on genuine coins to make them appear to be a rarer date and mint mark combination. Details can be added or removed. Look for scratch marks, glue spots and changes in color.

Drop the coin on a hard surface. Genuine ones make a ringing sound when dropped. Fakes make a thudding sound. Do not perform this test if the coin is in pristine condition or especially valuable.