Made with Black Onyx Features our petite 4mm size which is about 1/6 of an inch. Metal Components: Solid 14K White Gold. Hallmarked. Professionally hand-set in our own US studios. Style or Setting: Cup post for Pierced Ears. Experience the beauty, elegance and mystique of classic Black Onyx. This set features our petite 4mm Black Onyx Ball Stud Earrings on solid 14K White Gold posts. Simply gorgeous and always in style.