Wow! This is a Stunning Example of Victorian Revival Bookchain Necklace with Large fully functional Locket. The chain necklace measures appx 18 inches with a 1 inch drop. The locket is 2 inches long and nearly 5/8 inch thick. Fold over clasp. No hallmarks, look like it could be German or even 800 Silver. Enamel inlay on surface. I believe this is an English piece.