What Are Sweet Water Pearls?

by Stephanie Gaughen ; Updated September 28, 2017

Sweet water pearls are harvested from freshwater mollusks found in freshwater lakes and rivers. Officially referred to as freshwater pearls, they are primarily used for jewelry.


Freshwater pearls primarily originate in China, Japan, Thailand, Vietnam, India and the United States. Commercial cultured freshwater pearl crops began at Lake Biwa, near Kyoto, Japan, in the 1930s. China began selling cultured pearls in 1968.


Freshwater pearls form when a foreign particle, usually a microscopic parasite, appears in a freshwater mollusk, sending the mollusk into a defensive mode. To reduce irritation, the mollusk coats the foreign particle with nacre and a pearl is formed.

Cultured Pearls

Since natural pearls are very rare and usually only sold at auction, farmers try to replicate them to sell in mass quantities to retail shops. Cultured pearls are formed when the farmer physically places mantle tissue into the mollusk, tricking the mollusk into forming a pearl as it prepares to defend the foreign particle.


There are more than 350 species of freshwater mussels that can produce freshwater pearls, but the most common is Hyriopsis Cumingii.


Freshwater pearls range in size from 2mm to 18mm.


Freshwater pearl colors include white, cream, gold, silver, pink, rose, lavender, plum, tangerine and mocha.

Photo Credits

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About the Author

Stephanie Gaughen holds a bachelor's degree in news-editorial journalism from the University of Nebraska at Kearney. She has worked as a photojournalist and copy editor at two regional daily newspapers, and as a corporate communications writer.