How to Know That My U.S. 1-oz. Gold Eagle Is Real

Check the weight of your coin on a set of scales. It should weigh slightly more than 1 oz.--1.0909 troy ounces, to be exact. This is because, as well as 1 oz. of pure gold, the coin contains small amounts of other metals to make it more durable. As gold is heavier than most base metals, a counterfeit coin will probably be much lighter than 1 oz.

Measure the diameter of your coin with calipers. This should be 1.287 inches. Any variation will again point to the coin being counterfeit.

Inspect the coin's design under a jeweler's loupe, paying particular attention to details of fabric and hair and the edges of letters. A real gold eagle will hold plenty of crisp detail, whereas a counterfeit will disappoint with slight imperfections and blurry edges. A fake proof coin should be especially obvious, as the real thing is finished with a luster that combines mirrored and frosted elements--the sort of painstaking details that forgers usually omit.

Examine the accompanying documentation. With bullion coins there should be evidence that the coins were bought at some stage from an authorized broker, while proof coins should have a proof of purchase from the U.S. Mint itself, as well as a Certificate of Authenticity and special packaging. If a gold eagle has no accompanying documentation of any kind, then you should be very suspicious.