It's a birthstone for May I think. Call the school and let them know you found it, might be a small school that could help you track down the owner? The real owner will probably be able to tell you where it was found. All the symbols on the side are stuff the student was involved in possibly, so that might narrow it down. The Reeds located nearest that town might very well be the one who sold that ring and may be able to locate the owner.
Or finders keepers... I dunno. I think part of the fun for me is solving the other half the mystery, of how it got there & returning it to the owners.