Navy blue satin evening gown with crystal belt

I lost my navy blue satin floor-length evening gown, size 6, by Adrianna Papell, yesterday around 3pm near the Campanile on the ISU campus in Ames. It's a formal wear dress with a detachable crystal-embellished belt and a small silver zipper at the back. The fabric has a faint snag along the left hem and the belt clasp is a bit stiff in the middle, which makes it easy to spot if found. It means a lot to me — it was a gift from my grandmother and I'm really hoping to get it back.