Freshwater pearls are a type of pearl which grow in non saline environment in freshwater mussels. The pearls appear in a wide variety of shapes and natural colors, and tend to be less expensive than saltwater pearls, therefore; making them very popular among younger people and designers. Freshwater pearls are quite durable, resistant to wear and chipping and degeneration. Presently, they are almost exclusively produced in China, with some limited production in the US and Japan.
The Japanese have a special history as the first country to cultivate cultured freshwater pearls in Lake Biwa, using the Biwa Pearl Mussel. However, it came to a halt during its peak production in the 1970s, due to pollution in the lake. The Japanese attempted to farm freshwater pearls once more at Lake Kasumigaura, using a cultured bead- nucleated hybrid mussel. The Kasumiga pearl industry had a short lifespan and ceased production in 2006, also as a result of pollution.
The United States
The Tennessee pearl farm, led by John Latendresse and his wife Chessy, was the only freshwater pearl production outside of Asia through the 19th Century. However, over harvesting and increased pollution significantly decreased the amount of available pearl- forming mussels, which stopped the freshwater pearl production. At present, the pearl farm has emerged as a tourist attraction.
Presently, China is the only commercial producer of freshwater pearls, producing 1500 metric tons per year using the triangle shell mussel and several hybrid methods. The first record mentioning pearls in China dates back to 2206 BC. The birth place of the pearl industry is traced back to the area around Shanghai; however, freshwater pearls are now produced in all the surrounding provinces such as: Zhejiang, Anhui, Jiangsu, Hubei, Hunan, and Jianxi. Local pearl trade is conducted mainly in Zhuji (Shanxiahu), Suzhou, Wuxi, Wenling, and Weitang. The largest marketplace for freshwater pearls is Hong Kong, where it is also the world’s pearl trading hub.
Freshwater pearls come in many shapes, colors, and sizes. Cultured freshwater pearls can be dyed yellow, green, blue, brown, pink, purple, or black. The pearls also range from round to button shape, and from flat flakes to rice shaped.
Traditionally, sources of pearls have been in saltwater mollusks, freshwater mussels, which live in ponds, lakes and rivers. Most of the freshwater pearls are not bead- nucleated. Rather, they are nucleated by creating a small incision in a 6 to 12 month old mussel, then are inserted a piece of mantle tissue from a donor mussel. In the past, it was common practice to insert 25 tissue pieces in the mantle of each valve. However, presently only 12- 16 pieces are implanted in either valve, producing 24- 32 pearls per mussel, which increased the quality of the pearls. The mollusks are returned to the freshwater environment where they are tended for 2 – 6 years. The resulting pearls are solid nacre; layers of crystalline and organic substances protecting the mollusk to form a pearl.
Over the past few years there has been a significant increase in the quality of Chinese freshwater output due to different production methods.
The major increase in quality can be attributed to replacing the Cockscomb pearl mussel to the Triangle Mussel in the mid 1990’s. The Cockscomb was responsible for low- quality pearls known as rice- crispy pearls in the 1970s and 1980s. The switch to Triangle Mussel significantly increased the higher- quality production, and is widely used by Chinese farmers to culture freshwater pearls.
Biwa Pearl Mussel
Introducing this new mussel om Chinese freshwater pearl culture has lead to even higher quality cultured pearls in more saturated colors and larger sizes. The mussels had greater vitality and produced better pearls overall. Experimenting a cross- bred of a Triangle mussel and Biwa mussel, created a hybrid that is superior. This hybrid changed the course of Chinese freshwater pearl culture.
Fireball Cultured Pearls
While the world was introduced to the Biwa pearl mussel and it’s triangle mussel, a new pearl gained popularity, the bead- nucleated freshwater pearl, known as fireball or CBSB (coin-bread/spherical bread).
The CBSB process starts with an incision of a coin bead, and a 1 mm square piece of mantle tissue in a three-year-old triangle mussel. The host mussel’s mantle encloses the coin bead and begins to create a one-tear coin pearl.
After the first year, the farmer can either remove the coin pearl and return the mussel to the water to create a keshi pearl, or can leave the mussel in the water to add nacre to the coin pearl. Regardless of the decision, this second step takes an additional year.
The third step, is the production of freshwater pearls that have a spherical bead nucleus. When the mussel is five years old, the farmer removes either the coin pearl or the keshi, and inserts a spherical bead nucleus in the pearl sac. The pearl sac forms a bulge in the mantle, creating a perfect nacre- production pocket. The pearl’s growth period ranges from one to two years. The result is a bead- nucleated pearl with a substantial size.
There are certain factors that contribute to the overall value of freshwater pearls. In general, freshwater pearls are less expensive than saltwater pearls, but due to new production methods, freshwater pearls are a great alternative for many who are looking for good value and fine quality. With improvement of its cultivation methods, low labor costs, and vast number of unpolluted lakes, China has created a pearl industry that can offer very competitive prices. In addition, physical properties also determine the value of the pearl, such as the color, shape and the thickness of the nacre.