14k gold necklace with emerald pendant, 18-inch

I lost my 14k gold necklace with an emerald pendant yesterday around 3pm near the Covered Market entrance on Cornmarket Street, Oxford. It's an 18-inch chain, pretty polished but with a couple of tiny scratches from daily wear, and the pendant is a small square emerald about 8mm across. There's a tiny bee charm etched on the back of the pendant, and the clasp has my initials 'AR' engraved. This necklace was a birthday gift from my grandmother, so it means a lot to me and I’d be really grateful to get it back if anyone found it. If you found it, I’d be grateful to hear from you—you can email me at [email protected].