Square Black diamond Silver Stud Earrings

Elegant square stud earrings with small black diamonds. They were a gift from my ex over a decade ago and I just found them. He said they are black diamonds, I did not go with to purchase so I can’t be 100%. Thought someone else could wear them since I haven’t in ages. Please see the silver part of the back where it’s black, I think the coating has come off? Not sure. Open to offers!