I thought it was marked but I can't find it so I could be wrong. But I don't think it's plated. I have terrible allergies to alloy metals. And I didn't break out when I wore it. I loved this ring! My problem is all my rings fit the same finger. Lol and my husband likes to get me anniversary jewelry so I have too many I can't wear. I decided to pass them on. The pictures honestly don't do it justice. But again to answer your question. I do not see a stamp. :(