Proof Coins "In The Wild"

Mint marks are the most telling feature on post-1967 coins. Except for a few special issues (P and W proofs), all proofs have been made at San Francisco, and business strikes are quite limited (1968-75 cents, 1968-70 nickels, 1979-80 SBA dollars). For ambiguous dates or coins from prior to 1968, you can supposedly tell by the sharp, squared off rims and higher relief- proof coins are struck at a greater pressure which results in deeper fields and higher devices, and the excess will be pushed up into the rim to make the coin appear thicker from the side.

Now if we're talking about early proofs (19th century to early 20th) all I know is that sometimes it can be very difficult. Some members on here, IIRC, have found circulated proofs mis-attributed as high grade business strikes. Some have even tried to pass off 1895 proof Morgans as one of the lost Philly business strikes from that year.

Somewhere among the piles of nickels I hoarded from rolls is a 1969-S that I set aside because I was pretty sure it was a proof. It had traces of mirror-like luster in the protected spots between and around letters, and it had very even rims. The consensus at the time was that it was just a business strike. I'll have to see if I can find it again to post pictures.

But, as has been stated here before, the distinction is just academic unless you are talking about 1940s or earlier proofs.

Finn235 and iontyre Yall are my official heroes today. THAT'S what I'm talking about--definitive, objective (not subjective) ways to be certain when possible, and acknowledgement that subjectivity should (and sometimes does) come into play only when objective certainty isn't possible. Can you tell I was a science major? Ha, but I totally believe that experienced coin hobbyists don't need mint marks or rim measurements to know a proof when they see it; I just wondered if there was something like a dichotomous key for newbs like me. I did know that proofs were only minted in SF, but not that SF minted only proofs (in any years), nor that there were physical characteristics beyond smoothness/reflectivity. --In that case an experienced collector could probably tell the difference blindfolded, even if the proof's field was badly abraded. Now I gotta go through all my wheaties again because I know I have seen that sharp, wide rim in one or more of them.
Okay so final question: is it that higher pressure strike itself that causes the ultra smooth field? It would make sense, like how the shiniest stones are created by pressure.

As I buy proof and mint sets that are post 1964 clad any coin that's not worth the money to 2X2 the coin I toss in my change jar for coin shows. Children get a kick out of getting this kind of stuff for change.

I'm not sure how rare it is to find. i'd think it uncommon, but not rare.

i found this 1971-S sorting through a sack of change earlier this year. I saw it right away, it practically screamed at me, being the only proof in the pile. wasn't sure I was seeing what I was seeing until I saw the mintmark, then I knew. it's the first & only proof I've found in circulation.

Nice, MrPink. I went to the laundromat a few days ago and snagged a 1977-S proof coin out of the quarter dispenser. I ALWAYS check my quarters when I go there and it is the only thing I have found so far. I feel eventually a silver is going to pop out of there.

@ mail187man

yep, they do once in a while. last one I found was in change from a home depot self-checkout machine, gave me a lowball canadian quarter, date worn away, it likely 80 yrs old or so, maybe older. also recently scored a silver dime, 63-D, from a parking lot. got a War Nickel in change this summer.