96 Unusual Striking Siamese Pearls - 10mm x 6mmPrice is per 15 inch string of these lustrous pearls. Maximum size in the strand is 10mm x 6mm x 4mm. About 96 beads to the string Centre drilled. Cultured pearls Most pearls these days are cultured. These 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