A coin collector must always keep a vigilant eye when purchasing new coins for a collection. Counterfeiting rare silver coins for profit is both a hobby and a business for many crooks, con artists and ne'er-do-wells. Many counterfeit silver coins are made to look so authentic that an untrained observer could not recognise any difference between a fake and the real thing. A watchful collector knows how to spot a fake and keep it out of a genuine collection. If you are just starting your collection, you can learn what to look for to tell if a silver coin is counterfeit.
Find a detailed, genuine photo of the type of coin you are trying to verify.
Compare the image on the front and back of your coin to the genuine photo. Differences will be subtle, but if your coin is counterfeit, there will be noticeable errors.
Observe the feel of the coin. Counterfeit coins feel more slick and slippery because of the inferior production methods.
Look for dents on the coin. According to Silver-Coins.org, these marks indicate errors in the die during manufacturing of the counterfeit.
Observe the date of the coin. According to the article "Detecting Counterfeit Silver Coins" found at CoinFreek.com, counterfeit coins made from poured liquid metal will have definite irregularity that can be seen in the date. The numbers in the date will appear crooked or misshapen.
Look at the edges of the coin. Genuine coins will have thin, even edges around the circumference of the coin. Counterfeit coins will either have abnormally thick edges or no edges at all.
It is virtually impossible to tell a counterfeit coin if you do not know what the real one looks like. The differences you are looking for when trying to spot a counterfeit are things such as the number and size of stars on the coin, the position of the date, the hairstyle of the person printed on the coin, the font of words embossed on the coin, and any other inconsistencies between your coin and the original. It is also a good idea to purchase a coin identification book for the purposes of verifying the authenticity of your coins. A good book to have is "The Official Guide to Coin Grading and Counterfeit Detection."
If you suspect that you are in possession of a counterfeit, do not attempt to return it to the salesperson. That person will probably be very difficult to find. Instead take it to a trained numismatist (coin collector) and have that person verify the coin as counterfeit. Be careful when purchasing coins over the Internet. If you cannot see the coin in person, you cannot verify the authenticity, even if the salesperson provides a "genuine photo."