Biwa pearls are freshwater pearls that come from mussels, and are arguably the most famous type of freshwater pearl. Over time, fishing and pollution have made it increasingly hard to find Biwa pearls in freshwater environments.
The authentic Biwa pearls come from Lake Biwa in Japan. Operations to start cultivating pearls in Lake Biwa began in the 1920s, with a popular run for decades until water pollution began to decrease the number of available pearls. The term Biwa initially described freshwater pearls and their unique shapes, although in modern times the term is generally used to describe the shape of a pearl. Freshwater pearls tend to be more affordable than cultured pearls, as it is easier to cultivate them in larger quantities.