Freshwater pearls differ in many ways from their saltwater cousins. While Akoya, Tahitian, and South Sea pearls are cultured in Saltwater oysters such as the Akoya (pinctada Fucata), the Black-Lipped Oyster (pinctada Margaritifera), and the Golden-lipped Oyster (pinctada Maxima), freshwater pearls are most commonly cultured in freshwater mollusks such as the Triangle Shell.
When pearls are cultured in saltwater oysters a nucleus is inserted into the gonad, or ****** organ of the oyster. A small piece of mantle tissue is then inserted along side this nucleus. This piece of mantle tissue produces the pearl sac that deposits the nacre around the nucleus producing the pearl.
Freshwater pearls, on the other hand, are cultured with only the piece of mantle tissue from another donor freshwater mollusk. This piece of tissue is placed inside the mantle on either side of the bivalve. As this is the muscle connecting the mollusk to the shell it is much larger than a gonad. It is capable of accepting 25 implants on either side, for a possible harvest of 50 pearls in a single mollusk.
When the freshwater pearl is harvested it is then drilled, and the mantle tissue used to nucleate the pearl is either dissolved or drilled out – you are left with a solid pearl. This is unlike the various saltwater pearl varieties that still contain the nucleus in the finished product. Why, then, is the freshwater pearl so much less valuable than all the others, one might ask.
The first reason is the ease of the culturing process. An Akoya oyster can theoretically hold up to five nucleations, although more than two is nearly unheard of. Tahitian and South Sea oysters may only be nucleated with a single nucleus at a time. Freshwater pearls, on the other hand, will produce 35-50 pearls per mollusk consistently.
Although the culturing time for a freshwater mollusk is 3-5 years versus the typical 2 years for a saltwater pearl, the cost, the risk, and suitable farm locations are all in favor of freshwater pearl farms. Even with a mortality rate of 25% (half that of any saltwater farm), the harvest is almost always good. Freshwater pearl farms rarely have to deal with weather and natural disasters (such as red tide) that constantly plague saltwater farms.
Another reason freshwater pearls do not value as high as their counterparts is their aesthetic appeal. Freshwater pearls are rarely round. They may be close to round in their highest qualities, but almost never achieve the spherical shape of a saltwater pearl. A freshwater pearl will also rarely have the brilliant luster and shine of a quality Akoya pearl. For this reason, freshwater pearls are mainly used in design jewelry that places more value on the design of the piece versus the cost of the product. If one were to venture into a high-end jewelry store such as Tiffany’s they will a wide array of quality Akoya, Tahitian, and South Sea pearl jewelry, but only designer jewelry composed of freshwater pearls. When freshwater pearls have been value-added in this way they can fetch a good price in a retail store.
A final reason freshwater pearls have a lower value than others is their abundance. 15 years ago freshwater pearls were nearly exclusive to lake Biwa in Japan. A decade ago nearly all pearl farms were shuttered due to pollution in the lake. Japan has never recovered its freshwater pearl industry. Until recently, with lake Kasumigaura boasting a small harvest of quality freshwater pearls, Japan has merely imported its freshwater pearl requirements from China.
China is where freshwater pearls come from today. It is said in many parts of China that anyone with a small plot of land and access to freshwater either has, or plans to have a freshwater pearl farm. Tens upon thousands of freshwater pearl farms have popped up all around China in the last two decades. Because of the intense local competition prices for freshwater pearls have been dropping at a steady rate since the mid 1990’s. Even as quality increases, prices continue to drop. A strand that would cost $5-600 in 1995 (and still may at a jewelry store comprised of unturned stock) may only cost $75-125 in a local beading store today. The only freshwater pearls that still hold value today are those with clean surface, high shine, and very near-round shapes – or less than 3% of a farms total harvest.
Chinese freshwater pearls are very popular in China, and a huge export. Pearl markets dot the cities throughout China, like Hongqiao Market in Biejing, and Pearl Village in Shanghai. These markets are mainly targeting local shoppers and tourists, however, and high-quality pearls are a rare. Serious buyers attend Chinese tradeshows and visits local farming communities such as Wuxi and Nanjing. The highest-quality pearls rarely leave these areas unpurchased by a major international buyer.
This is not to say, of course, that freshwater pearls are not good pearls and that one should stay away from them by any means! Let us not forget that freshwater cultured pearls are still genuine pearls. They are also solid nacre – they will last a lifetime. Freshwater pearls are also a very good gift for the value-conscious. It is possible to obtain a nice freshwater pearl necklace for well under $100. It is impossible to find a high-quality Akoya pearl necklace of any size in this price range on a retail level.