Gold heart pendant necklace with engraving

Yesterday around 3pm I realized my necklace wasn't on me. It's a delicate gold-tone heart pendant on an 18-inch chain, about as long as a standard necklace, with a small scratch on the back of the heart and a slightly loose clasp. The engraving inside the back reads 'M'—hard to notice unless you flip it over. I was walking around Broad Street Market in Harrisburg, near the entrance by the vendor stalls, and I must have dropped it along Market Street somewhere between the coffee shop and the pet store. It was a gift from my sister, and it carries a lot of sentimental value; I’d be incredibly grateful to get it back if someone picked it up.