Believe the pros before me ALWAYS - but I think it looks copper plated. Put "copper plate quarter" into your favorite search engine and search videos. It's a fairly easy experiment a lot of people do. I can't tell from the pics but look closely at edges and see if you can tell if/where an alligator clip was attached.
Edit: Many quarters found in the ground metal detecting get a tone like this as well.

Edited by DeadElvis
04/27/2020 3:49 pm