14k gold necklace with ruby heart pendant

I lost my 14k gold necklace with a ruby heart pendant yesterday around 3pm near the corner of Walnut Street and 18th Street, outside the La Colombe on Rittenhouse Row. The chain is delicate, about 16 inches, with a spring-ring clasp, and the pendant is a 6mm ruby heart with a tiny scratch along the back. There's a faint engraving on the back that reads 'Nia' and the whole piece has a warm, rosy glow when the sun hits it. It was a gift from my grandmother and feels incredibly sentimental to me—I'd be beyond grateful to get it back through any lead.