Trustmark 925 Sterling Silver 4mm Created Royal Lavender Opal Ball Stud Post Earrings, Elizabeth Features our petite 4mm bead or ball size which measures about 1/6 of an inch. Style or Setting: Solid 925 Sterling Silver Cup post for Pierced Ears. Professionally hand-set in our own US studios. Posts and backs feature an anti-tarnish finish. Please note that these are small, petite earrings.