Although the traditional source of pearls has been oysters which live in saltwater, mollusks which live in freshwater lakes and rivers can also produce pearls. China has harvested freshwater pearls for many a millennia. The first record mentioning pearls in China was from 2206 BC. The United States was also a major source of freshwater pearls from the discovery of the New World up through the 19th century, when over-harvesting and increasing pollution significantly reduced the number of available pearl-forming mussels.

Freshwater pearls are often somewhat less lustrous* than their saltwater counterparts. However, they appear in a wide variety of shapes and colors, and they tend to be less expensive than saltwater pearls, making them quite popular. Freshwater pearls are also quite durable, resisting chipping, wear, and degeneration.

Freshwater pearls differ from other cultured pearls* in that they are not bead-nucleated. Freshwater mollusks are nucleated by creating a small incision in the fleshy mantle tissue and inserting a piece of mantle tissue from another oyster. This process may be completed 25 times on either side of the mantle, producing up to 50 pearls at a time. The mollusks are then returned to their freshwater environment where they are tended for 2-6 years. The resulting pearls are of solid nacre*, but without a bead nucleus* to guide the growth process, the pearls are rarely round.

In recent years the Chinese have been able to take the art of culturing freshwater pearls to new levels. In the last decade the quality of pearls produced have become so high that many pearls in the top percentage of a harvest are nearly indistinguishable of their saltwater relatives. Gone are the rice-shape seed pearls as they are now being replaced with round, lustrous pearls of sizes as large as 16mm, mimicking large South Sea pearls. This has created a renewed interest in freshwater pearls as an affordable alternative to the higher priced saltwater.

The Japanese have a distinguished history of culturing freshwater pearls as well. Lake Biwa was once world renowned for producing high-quality freshwater pearls. However, in the mid 1970's pearl farming all but came to a halt due to pollution in this lake that was once synonymous with freshwater pearls. Today the Japanese are trying once again to farm freshwater pearls in Lake Kasumigaura, utilizing a bead-nucleated hybrid mussel (yriopsis Schlegeli anadonata/plicata hybrid mussels). The resulting pearls have been quite large and unique. But due to the high prices of such pearls the market remains a niche for collectors.

HouseofGems.com would like to thank Pearl-Guide.com, for this informative article.