Gold-tone heart pendant necklace, 18-inch chain

I was at the downtown Mason City Farmers Market yesterday around 3pm and realized my necklace was gone. It's a gold-tone dainty necklace with a tiny heart pendant, about 18 inches long, from the brand Aurora. The back is engraved with an initial 'L' and there’s a small sapphire at the heart corner. The chain is slender and the clasp is a simple spring ring. It has huge sentimental value—it was a gift from my mom—and I really need it back. I last noticed it near the Mason City Public Library on 2nd Street, close to the corner cafe, as I headed toward Main Street. If found, please reach out; I’d be incredibly grateful.