Freshwater Cultured Pearls
Although originally produced in Japan, 90% of the world's freshwater pearls now come from China. Unlike other pearls on the market, freshwater pearls typically do not come from an oyster at all. Most such pearls are farmed in varieties of freshwater mussels, including Hyriopsis and Cristaria. Each shell can produce up to 100 pearls simultaneously.
Most freshwater cultured pearls are nucleated with pieces of mantle tissue - rather than a round nucleus, which is placed directly into a mussel's mantle to initiate nacre production. Mantle tissue is shell material that is recycled into the formation of new pearls. As with Akoya pearls, freshwater pearls are not marketable for jewelry in their natural state, and require clinical enhancements such as bleaching, coloring, and polishing.
Traditionally, most cultured freshwater pearls grow in irregular shapes from near round to oval, between 2.0 to 5.0 mm. New farming and pearl-enhancement technology has enabled the production of more round pearls and a whole new array of colors, now producing freshwater pearls in sizes up to 9.5 mm. Supply is plentiful and quality is highly variable, consequently the price of freshwater pearls varies and is generally lower than other cultured pearls.