Trustmark 925 Sterling Silver 6mm Faceted Fiery White Created Opal Screw Back Stud Earrings, Lorraine The white background of the opals glitter with flashes of a multitude of colors from blue to green to pink. Hard-to-find threaded posts with screw-on backs! Made with solid 925 Sterling Silver with a White Rhodium Finish. Professionally hand-set in our own US studios.