My grandma gave me a ring and it looks like it was made from a coin. Dated on front 1917 and back says united states of america, and then says "one" and a little more but i cant make it out.
it is a 'repousse' punched coin turned into a ring, and as Charlie stated above, it began life as a Mercury dime. hard to say how long it's been a ring as this process was popular many years ago but still done today