I inherited these from my grandmother after she passed, I believe my grandfather may have brought them back with him as he was a Sgt. in WWII but i'm not positive. The back of the clasp says Japan so that makes me wonder if it's just costume jewelry. The pearls are different sizes ranging from 1cm (10mm) to about .5cm (5mm) and they are heavy. They are a little gritty when rubbed against my teeth. I'm really curious as to if these are worth anything, it would be nice to have a little nest egg set aside for my little one. Thanks for any help!!!