Please help! Lost engagement ring! Heartbroken!

I lost my engagement ring on Rehoboth Beach, DE yesterday afternoon, and am absolutely devastated. It was secured in a pouch in my sunglasses case in my beach bag, but must have somehow fallen out. It's a simple ring: gold band, one small diamond. Probably not worth too too much, but it's EXTREMELY SENTIMENTAL to me. It was finance's grandmother's ring, and it is the most special object I have ever owned. We looked through the sand with sifters and shovels for hours yesterday, but could not find the ring. I would do anything to get this ring back. I will pay a reward if you find it. Thank you so much for your time.