I know they are 13 mm and I paid $900 to a lady who brought them back from overseas on a pearl trip. She brought pearls for many of her Beverly Hills clients and I happened to know one of her clients. I do not know what part of " over seas" she brought them from. The claps I assume is sliver because it's tarnished and I need to clean. These have been in my drawer since 2005. I wonder how much they are worth. Let me know if the pictures don't show up.