The least expensive cultured pearls today rival the most expensive natural pearls ever found
Natural freshwater pearls occur in mussels for the same reason saltwater pearls occur in oysters. Foreign material inside a mussel can't be expelled. To reduce irritation, the mollusk coats the intruder with the same secretion it uses for shell-building, nacre. To cultivate a pearl, farmers slit the mussel and insert small pieces of live tissue from another mussel.
The ancient Chinese practiced this technique, but the first real cultured freshwater pearls originated in Japan. In the 1930's, Japanese farmers by Lake Biwa achieved natural colors unseen in saltwater pearls. However, water pollution today has virtually destroyed pearl production there.
China has the resources that Japan lacks: many large lakes, rivers, and a low-cost work force. The first Chinese cultured pearls were basic, until the 1990's when China revolutionized pearling. Shapes, luster, and colors of the new Chinese pearls now surpass Biwa quality.
