Natural freshwater pearls occur in mussels for the same reason that saltwater pearls occur in oysters. Foreign material, usually a sharp object or parasite, enters a mussel and cannot be expelled.

whereas Japanese pearls were found near the coast in salt water. Nearly all the pearls in commerce originated from those few sources. Over the next millennium only three substantive events altered ...

What makes the Bird on a Pearl capsule collections so special is that they are made from extremely rare natural saltwater pearls. Due to the increasing pollution in the world's oceans, natural ...