This is a necklace from the French accessory brand Nature Bijoux. The polka dot pattern, which appears to be made of inlaid shell, is stylish. It has only been tried on and never worn, but since it is from a few years ago, if you look closely, there might be some oxidation on the metal parts, but I don't think it's noticeable unless you look very closely. The pendant part is made of a surprisingly lightweight material. It is unknown what it is made of.