Trustmark 925 Sterling Silver 10mm Natural Purple Amethyst Ball Stud Post Earrings Made with Natual Purple Amethyst Features our bold 10mm size which is about 4/10 of an inch. Metal Components:Solid 925 Sterling Silver. Hallmarked. Professionally hand-set in our own US studio. Style or Setting:Cup post for Pierced Ears. All our diamond suppliers confirm that they comply with the Kimberley Process to ensure that their diamonds are conflict free.