Shell necklace

This is a beautiful piece of jewelry. Selling for a friend. Have any questions just ask. Shell pendant is approx 1.5” x 2.5” and the necklace is stamped . I tried to use a magnifier app to read what it is stamped with but it’s so teeny it’s impossible. I notice some tarnish on the chain accounted for in price. See picture 6 for location. This is not my piece and the owner said firm unless bundled with another item she would consider reasonable offers so send them my way and I will relay.