Many people still refer to freshwater pearls as Biwa pearls. Lake Biwa in Japan was indeed one of the first farms in the world to produce cultured freshwater pearls. Sadly, due to pollution and competition from china, production has halted. At first, China, with its low labour costs, was only able to create low grade rice shaped pearls, but, over time, they have honed their skills in order to produce pearls from cheap rice shapes to gem quality rounds.

Freshwater pearls are cultured in a similar way to Japanese pearls with the main difference being the use of a muscle, the Hyriopsis Schlegeli, in place of the ubiquitous Oyster. A piece of mantle tissue from another mollusc is grafted into the muscle where a pearl sack forms around it as it gradually disappears. This is the reason that freshwater pearls are non-nucleated. Pearls can grow to virtually any size, depending on the length of time that they are left in the water. Necklaces with 14 or 15mm centre pieces are now possible, but still very rare.