That's an awesome Russian half kopeck or ''polushka'' from the reign of Anna of Russia. It's crazy for them to end up where you are but I have seen some occasionally. They are pretty uncommon even in Europe. Congratulations!
I am normally more of a coin guy, but for some reason, I really like that dog clasp. I am not a dog owner, but it is such a unique and personal piece. Congrats on the great finds.