The OED lists the definition or Error as
(1) A mistake or (1.3 technical) A measure of the estimated difference between the observed or calculated value of a quantity and its true value.
In the world of coins, the 1.3 definition is much more important than the 1 definition, as error coins are, generally, worth more than their perfect cousins!
How Do We Get Error Coins?
An “Error Coin” in the numismatic world is a coin that was manufactured incorrectly by the mint, and these mistakes were never intended for release to circulation. These problems come from the manufacturing process, which up until recently, involved people doing the tasks that are now performed more and more by machines.
Types of Error Coins
These mistakes are sought after variations from normal coins for their uniqueness, how they shed light on the minting process and the disparities from said normal coins. The types of error coins listed by the Red Book are: Clipped Planchet, Multiple Strike, Blank or Planchet, Defective Die, Off Center, Broadstrike, Lamination, Brockage, and Wrong Planchet.
I will go into detail on each of these types in further posts. In fact I will flesh out some of these into more specific categories, but as a rule, the names given are pretty descriptive of the cause, no strange words being used here by the coin world.
Value of Error Coins
The value of any error coin is determined, …..wait for it, by the market (supply and demand). And this I mean that collectors value the coins by their scarcity of the error for each type of coin. A coin that has a mintage of 100,000,000 and has 2 errors is worth way more than a coin that has a mintage of 100 and has 2 errors.
But the Mint Has a Plan
Obviously, error coins are a “black mark” for the mint, as they want to put out perfect products all of the time. So they have been working on removing these possible errors from the public. In 2002, the mint changed the process of the production to try and remove off center strikes, deformed planchets, and the like. They also changed how and where coins are sorted and sent to banks so that after 2002 almost no error coins have hit the market. So if you have an error coin dated after 2002, call us!