Chinese Champagne Rice Pearl StringPrice is per 15 inch string of these light champagne 5 x 3mm pearls. Ideal for reselling or stringing. The least expensive cultured pearls today rival the most expensive natural pearls ever found. Natural freshwater pearls occur in mussels for the same reason saltwater pearls occur in oysters. Foreign material inside a mussel can't be expelled. To reduce irritation, the mollusk coats the intruder with the same secretion it uses for shell building,