Shipwreck Beads Blister Pearl Shell Drop Pendants, 50 by 60mm Average, Silver Drop pendants Made of blister pearl shell A blister pearl forms when a foreign object invades, or is implanted into the body of a mollusk, usually an oyster or a mussel Regular pearls form in the soft flesh of the creature, while blister pearls form against the animal's shell Available in 50 by 60mm average size and silver color