Fresh Water Pearl
Freshwater pearls are produced by Hyriopsis cumingi (triangle shell) and Hyriopsis schlegeli (Biwa shell), and other bivalve mussels that live in lakes, riverbeds and creek bottoms (mostly in China and Japan, as well the United States Mississippi River Basin).
Freshwater farming has some advantages over the seawater process. Freshwater pearls can be seeded with just mantle tissue instead of a bead of mother-of-pearl or other material. Cultivators place the foreign mantle tissue in the mantles of the host mollusk. After an elaborate process in which a single resilient mussel can be harvested many times, yielding several pearls …
