Trustmark 14K Yellow Gold 4mm Created Opal Ball Stud Earrings Lorraine: Simply elegant, these beautiful White Created Opal ball stud earrings are a great addition to anyone's wardrobe. Style or Setting: Ball stud earrings. Made with solid 14k Yellow Gold. Professionally hand-set in our own US studio. Each stone measures about 4mm in diameter (approx. 1/6").