Large Silver Black 10mm Pearl Rondelle BeadsPrice is 15 inch string of these beautiful freshwater pearls. Average largest measures about 10mm x 7mm about 54 to the string. 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