Silver-tone necklace with crescent moon charm

I lost my silver-tone necklace yesterday around 3pm near the Lawrence Public Library on Massachusetts Street. It's a mid-length chain, about 16 inches, with a lobster clasp that can stick when it's chilly. The pendant features a tiny crescent moon and a freshwater pearl bead; the back of the moon charm is engraved with the initials 'A.R.' and the chain has a couple of small scratches from daily wear. This necklace has sentimental value to me—my mother gave it to me before college, and I really need it back. If anyone finds it, please drop me a note; I’d be so grateful to get it back.