You may have a big fortune lurking in that bottle of unused coins sitting on your dresser. Have you heard of coin errors? If not, read on, and even if you have heard of coin errors, you may be surprised what is considered an error!
Despite the best efforts of mints the world over, errors do occur. They can range from something as trivial as a small crack in the die used to strike the coin, resulting in a small raised hairline type effect, to something as serious as forgetting to put a date on the coin. Machines make the coins but humans run them and the expression "to err is human" is proved time and time again. The fact that most of these mints run their production facilities around the clock means that sleep deprivation can play a big role in some of these errors. The midnight shift worker that puts the wrong reverse or "tail" die in the press can generate a nice quantity of error coins before that mistake is caught and depending how the actual production workflow is setup, it may not be worth looking for a few thousand coins in a production run of several million.
Curious what a coin error looks like? Reading a book on the subject is a start as many errors are well documented by coin collectors, but sometimes just looking closely at a coin may reveal something that a casual glance, and who really looks closely at their change, would not. The common expression of a " two headed coin" while catchy is unlikely because the physical dies used to strike the coins are different and two dies the same, two heads or two tails cannot be inserted into the equipment by accident. By accident is the key here, a couple of unscrupulous employees , one to machine the die, and one to insert it in the press, could do this, and it has happened. This type of error is actually not considered an error since it is made on purpose. A more interesting error can occur when a mint also manufactures coins other countries, with perhaps different alloys. What can happen here is that an error coin can be a coin of one country made with the alloy of another, or the obverse or reverse , the head or tail can be from a different country. This is a great error coin that is rare yet documented.
Coin error hunters love nothing better than being the first to spot something. This usually starts a flood of speculation among the collectors on how many may exist and what may have caused the problem. The mints are usually tight lipped about most mistakes, but coin errors are not really errors. Sometimes during a production run a change has to be made to a design to improve performance of the dies. This will lead to the remaining production being different, creating a sometimes small production run of one of the designs. These small runs can be in high demand because of their scarcity, but in the true sense of the word they are not errors.