Biwa Pearls, sometimes called stick pearls, are a type of cultured, fresh water pearl grown from a variety of mussels living in Lake Biwa - a large lake in southern Japan near the city of Kyoto. Dating back to the 1930's, Biwas were one of the first commercial ventures in the farming of cultured pearls.
Biwa pearls are pure nacre and grow in an elongated form (hence the name "stick pearls".) They have a good luster and a wide range of natural colors.
Biwa pearl farms were very active from Post WWII through the 1970's. Sadly, production has tapered off in recent years due to environmental issues in the lake.
Occasionally, other fresh water pearls are sold as Biwas, however in the USA only pearls from Lake Biwa can be legally marketed under that name.