Big Size White Coin 13 mm Cultured Freshwater Pearl Stud Earrings Brand New White Freshwater Cultured Pearl Pearl Shape: Coin Pearl Size: 13-14 mm Clasp Material: 925 Sterling Silver Hypoallergenic Tarnish Resistant Will come in box Pearls are the only gems that are produced by an animal. Cultivators mimic the way natural, uncultured pearls are created by implanting a beadlike nucleus from a mollusk shell into an oyster, and the animal responds to the irritant by coating it with a pearlescent nacre of calcium carbonate, layer by layer, multiple times per day. In this article the sizes and shapes of freshwater cultured pearls are approximate, therefore no claims are accepted for this reason. To preserve this jewel, it is recommended not to expose it to direct contact with creams and perfumes.