If AU58 denotes a coin that is About Uncirculated and the next grade up is MS60, does this imply that a Mint State coin has not been circulated, ever, at all? Put another way, can a MS coin ever be found in change? What is the exact definition of "Uncirculated?"
Good question. My thought has been that an MS coin is still in 'Mint State', which means that it could have circulated some, but hasn't been handled enough to remove the original mint luster, and not enough to cause wear to the devices. The literal definition of uncirculated, would be a coin that has never been released to the general population for its intended use. I think the term 'uncirculated' is a misnomer, and becomes a catch-all for coins that show no noticeable wear.
An Uncirculated (or, therefore, Mint State; don't let anyone tell you the terms have differing meanings, they're synonyms) coin is one which shows no sign of circulation to an expert eye. That's the only possible definition, because very darn few Business Strike coins are in a controlled chain of ownership from the moment they leave the Mint property. It's all subjective. So, yes, you can find a Mint State coin in pocket change from that standpoint, but no, you can not because if it's in your pocket you know it's circulated.
You'll usually never know if a particular coin has been in circulation or not (except coins in OGP), You will be able to tell if that coin has wear from circulation or not, though. It's the lack of wear that defines "Uncirculated" and "Mint state".
Uncirculated : A circulation-strike coin that has never been used in commerce, and has retained its original surface and luster; also called Mint State. From the 2017 Red Book Glossary. The next Grade after AU-58 is AU-59, the real question is how come it never gets used?
Liked this, so simple definition. (however, don't think you are so important just because he said "you". It's not your pocket which is important, they are pockets of presidents which determine a coin circulating or not. For ex., is there 1cent in his pocket of your president there? Certainly, no. So, 1cent is not in important pocket there and this means 1cent is uncirculated coin there.)
Just forgot to say that the mints are just factories, distributions of coins are usually made by dealers, for ex, by central banks. So, they too are responsible, but, they don't have either, 1cent in their pockets, therefore, presidents may blame dealers not bringing and putting 1cent into their pockets. (like a joke, isn't it..)
Pocket change in Mint state? When was the last time anyone saw a store clerk give you that change by holding on to it's edge...fingerprints that you cannot yet see?
But the new 2017-P cents you can find in circulation, are still are uncirculated. I found a 2015-D cents in circulation, submitted one of them for grading, came back MS68RD, pretty sure thats mint state -SC