18k-gold plated, mother of pearl MOP, crystal, Push-back post. For pierced ears.Diameter: 0.6" (1.5cm) Nickel-free Earrings.. The pre-loved Kira Stud Earring features a mother-of-pearl disc centered with our iconic Double T and bordered by milgrain — a row of tiny beads inspired by vintage jewelry-making techniques. A halo of crystals adds festive sparkle. For pierced ears.