What are Freshwater Pearls? 

Freshwater pearls come from freshwater mussels, unlike saltwater or Akoya pearls which form in oysters in a saltwater environment. For both types of pearls the process is the same - a small irritant in the flesh of the creature prompts secretions that eventually result in a spherical, glistening pearl.

While pearls created naturally in a saltwater source often have a "seed" at their center consisting of the original irritant, freshwater pearls (particularly those from mussels cared for in offshore "farms") have either no seeds or ones which are so tiny as to be virtually undetectable.

A variety of factors affect determine the shape and quality of freshwater pearls. These include the conditions in which the oyster or mussel is raised, the health of the host, water temperature and quality, etc.

How Freshwater Pearls are Cultured?
Since natural freshwater pearls are scarce and hard to find, the Japanese originated the first cultured freshwater pearls in Japan. To culture pearls, skilled workers open mussel shells just a slight crack, and insert smell pieces of live mantle tissue from another mussel into tiny slits made in the mantle.

This is usually enough to start nacre production, meaning cultured freshwater pearls generally have no sand or other material as a `seed` but are composed completely of nacre. 

The Japanese began experimentation in the 1950s with freshwater mussels in a large lake near Kyoto. This resulted in all-nacre Biwa pearls forming in colors previously unseen in saltwater pearls. These natural luminescent pearls with naturally occurring coloring became instantly in high demand.

Freshwater Cultured Pearls in China.

Although the Japanese dominated the cultured-pearl industry from 1950 to 1990, industrial pollution and over-development led to a steep decline in the quality of Japanese cultured pearls. The market shifted to China, where conditions were right for "pearl farming", since China has countless lakes, rivers, and irrigation ditches to use for pearl cultivation, and an eager work force that is ready to work the farms.

Currently the best and largest freshwater pearl producers are located in China. Modern technology and cutting edge techniques had been developed in Japan to process, clean, bleach, polish and drill freshwater pearls.

Chinese pearl cultivators studied Japanese pearl processing techniques and invested in the technology and research to become the best in the pearl market, creating natural pearls with great luster and perfect shape. Although cutting edge methods are used in most phases of work, most pearl stringing is still done by hand by skilled workers.

Freshwater Cultured Pearls and Natural Pearls.

The least expensive cultured freshwater pearls now available from pearl farms in China easily rival the pearl quality of the most expensive natural pearls in existence Chinese pearls are nearly indistinguishable from original Biwa quality, with size, color and luster often surpassing even the most expensive Japanese pearls.

Fred Ward, gemologist and author commented, "As testimony to China`s achievement, their freshwater pearls are round enough and good enough to pass as Japanese Akoya. China sells round white pearls to 7mm for about a tenth the price of Japanese cultured saltwater pearls."

"Aiming for an even higher percentage of rounds, the Chinese are even reshaping reject freshwater pearls into spheres, then nucleating mussels with them. That process and technique has radically altered freshwater culturing, making saltwater and freshwater techniques indistinguishable."

"After one experimenter used small off-round naturals as nuclei, he sent the resulting freshwater pearls to a gem lab and received a report identifying them as "naturals."

(Special thanks to Fred Ward, who is a gemologist and author of the book "Pearls" (Gem Book Publishers, Bethesda, Maryland, 1998). from which this article was excerpted in quotation and adapted.)