If you have been around error collecting much then you have heard or been involved in the "error versus variety" debate. This debate might never be completely satisfied for all parties involved, but for those who aren't aware of the debate, or weren't aware there was a difference between varieties and errors, I will highlight a couple points on the subject.
Coins, planchets or blanks mint errors are created during the creation of the alloy stock and all the way through the striking of the coin, but are casued by faulty machinary or a mint employees mistake, and all are actually unique. "Accident" and "unique" are the key words here since only errors occur by accidental machine or human error issues and typically no two are exactly alike, some are similar but never alike.
We know that several Capped Die mint errors for Lincoln Cents exist but they're rare and are always near unique, and even the Struck Through Die Caps are not alike. We will never have a few hundred let alone thousands of die caps for a certain coin type, date, mint or denomination so they will always be called mint errors.
A variety is any alteration to a die's design wether on purpose, planned or unintentional by mint employees, and authorized or not. A doubled die is unintentional and could even be considered a mistake or error but the fact is a doubled die is not unique and some of those exist in the thousands. Each doubled die variety is like the other except when it comes to die stages and states and that's caused by die fatigue and wear and is a common denominator for all of a dies life.
The 1922-D No D Lincoln Cent is an example of an unintentional die alteration, the mint employees were trying to extend the life of these dies to save money and eventually filed off the mint mark, and there's different stages and states for this, but each one is know for a few thousand examples that looks almost exactly alike. So this is when an unitentional mistake becomes a variety.
If you want to learn more about mint errors and varieties and see what they look like then visit our US Mint Error Page
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