The United States Mint is the organization that has the responsibility to produce coins that we use to make everyday purchases. With facilities throughout the U.S, the U.S Mint has been making coins since 1792. It's main facility is in Philadelphia, PA, but the U.S. Mint also has facilities in Denver, CO, West Point, NY and San Francisco, CA.
Through the use of machines that are able to cut and strike images onto pieces of silver and gold, coin making is a fascinating endeavor. Though every effort is made to make coins that are free of errors, this does not always happen. Sometimes during the early production of coins, an error is detected that causes an imperfection on the coin. Unfortunately for the Mint, some of these coins are sent into circulation before the error is discovered, making these very unique numismatic errors. Coin collectors love to track down errors made during production and these errors can make a coin much more valuable because of their relative rarity.
To give you an example of one of these errors, let's look at the 1955 U.S one cent coin which was created at the Philadelphia facility. During the production of a coin, a blank piece of circular metal is stamped a number of times with a die that eventually created a coin as we are familiar with. Unfortunately something went wrong with this process in 1955 and the penny had an error. If you look closely at some of these coins, you will notice that the letters have been stamped over twice, but not directly on top of one another. This caused the letters appear doubled.
Eventually U.S. Mint employees discovered the error but it was too late. Since they were ready to be sent out into circulation, it would be impossible to find the coins with the errors so it was decided that they would go into circulation and hope no one noticed. It wasn't long before the error was noticed and the coins value went up immediately. Just to give you an idea of what one of these coins, with a one cent face value is worth today – depending on the condition of the coin, it could go anywhere from $500 to $15,000!
While the U.S. Mint has processes in place so that coin errors are caught early, sometimes their best efforts are just not good enough. From a collector standpoint, this makes coin collecting even more interesting and it's a joy for many collectors to hunt down these irregularities. Because coins are created by machines at a fast pace using large machines, it's just not possible to inspect every single coin that passes by.
For the U.S. Mint, this coin errors are an embarrassing flaw in their production procedures, but for collectors and numismatics, these errors represent and unique and interesting opportunity. Whether you're an experienced collector or not, it might be worth looking at your pocket change more closely to see if you might be holding onto a unique error coin.