In the 1920s in Japan people started experiments to grow pearls in freshwater ponds, lakes and rivers. Before that pearls were only harvested in oceans. The first freshwater pearls came from Lake Biwa in Japan.
Right now freshwater pearls are mainly produced in China. It is much cheaper to produce the freshwater pearls in China, because the labour there is much cheaper.
The pearl mussel Hyriopsis Cumingi is used to produce the freshwater pearls. The pearl colour depends on the colour of the shell and can be white, purple, peach or pink. The pearls can reach sizes bigger than 15 mm in diameter, whereas the normal sizes are from 2 to 12 mm in diameter.