Trustmark 925 Silver 6mm Tropical Blue Created Opal Cabochon Crown Set Stud Post Earrings, Oceans Add the beauty and sparkle of the Tropics to your wardrobe with our Oceans line of created Opal ball stud earrings Features our stylish 6mm bead or ball size which measures about 1/5 of an inch. Made with solid 925 Sterling Silver. Professionally hand-set in our own US studio.