Beautiful coin.
I have a young lady friend who used to work at a nearby convenience store. She saved all of the silver and unusual coins for me and traded it at face value so her register wouldn't come up short. She has zero interest in coins. In about a year I got at least a dozen assorted coins.
She told me that in many cases, kids show up with them. They're probably breaking into Grandpop's (or someone's) collection to get candy and soda money. Some of the coins could have been sitting in some drawer for decades.
Sadly, she left the state and headed west. I really miss her as well as those coins. The new guy claims to be a collector. i think he started collecting the day I asked if he would keep saving them for me.
I also got a silver proof quarter in change about three years ago. I can't remember the year offhand. It looks like it was uncirculated as and someone broke into it and spent it candy and junk. Some kids just don't know any better.
And of course, the Coin Star treasures are always great. I used to get lots of silver from them but over the last few years people are wising up. I haven't found anything in well over a year. That's actually one of the reasons I got itno metal detecting. I want my coin collection to keep growing. the free ones are always more fun than the ones you buy.
Anyway, congratulations on the quarter. Even if it has no date, it's cool, it's old and it's SILVER!! It all adds up.