Purple Biwa Dancing PearlsPrice is per 15 inch string of these unusual pearls each measures about 7mm x 5mm x 4mm, drilled ready to thread. 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, nacre. To cultivate a pearl, farmers slit the mussel and insert small pieces of live