FRESHWATER PEARLS

Oysters that produce freshwater pearls are called mussels. A mussel can accept up to 50 pieces of mantle tissue at nucleation. The growing period for freshwater pearls is also much longer than other pearls, 2 – 6 years. Because freshwater pearls are nucleated with tissue only (not beads), they are rarely spherical. In fact, only about 2% are.

Chinese Freshwater Pearls

The quantity of Chinese freshwater pearls (aka sweet water pearls) produced today far exceeds that of Akoya saltwater pearls, and as a result of this production disparity, freshwater pearls are now significantly cheaper. Chinese freshwater pearls that are small and oblong shaped and are known as "rice pearls." Chinese freshwater pearls are also produced in "near-round" and "round" shapes.

In Chinese freshwater pearl cultivation, sheath tissue is implanted instead of a seed nucleus, and the tissue is implanted in the stomach of the mussel. Once harvested, the mussel is returned to the water, this time to produce a natural, or Keshi pearl called a "second-harvest pearl" where the original had been implanted.

In an attempt to compete with the Japanese in the field of large pearl culturing, the Chinese have been steadily increasing their output of 10+ mm freshwater pearls in recent years. This rapid increase in production has led to oversupply, and a corresponding increase in aggressive marketing and trade practices.

At gigantic "wholesale" pearl markets like the Yuyuan 'Pearl's Circles' market in the Shanghai Tianyu Tower, or the Hongqiao Pearl Market in Beijing you can be entertained by an endless chorus from hundreds of women shouting "mister, you want to buy pearls."

China dominates the freshwater pearl industry and has harvested freshwater pearls for many centuries in the 'zhuji' of China. World production and cultivation of freshwater pearls is dominated by the Chinese, who grown the mollusks in lakes, rivers, and ponds within the Zhejiang coastal region (aka "the hometown of pearl"). Most pearl farming in China take place within 480 km (300 miles) of Shanghai in the valleys of the Yangtse and its tributaries.

When Chinese freshwater pearls first appeared on the market, they were generally low quality; small, wrinkled pearls dubbed “rice pearls”. Chinese farmers knew to succeed in the market place, they had to focus on less production and improving shape and quality. Japan freshwater pearl farmers at Lake Biwa had been producing high quality tissue-nucleated pearls since the 1930’s. The Chinese pearl farmers observed the Biwa success thus improving their culturing techniques yielding higher quality pearls. Although “Biwa” pearls really are named after the Japanese pearls cultured in Lake Biwa, Chinese freshwater pearls are often referred by the same name.

Freshwater Pearls from Lake Biwa-ko

Freshwater pearls were cultured using the pearl mussels native to Lake Biwa . The widespread use of the 'Biwako Pearl Mussel' Hyriopsis schlegeli is reflected in the generic use of the name "Biwa pearls," and the name has now become synonymous with freshwater pearls in general.

Lake Biwako is fed by nearly 500 rivers that originate in the surrounding Hira, Ibuki, and Suzuka, mountains. During the peak production period of Biwa pearls in the 1970s, Biwako pearl farmers produced six tons of freshwater cultured pearls (FWCPs) per year. Since that time, pollution, a devastating freshwater red algae bloom (red tide), and over-harvesting have caused the virtual extinction of the Biwa Hyriopsis schlegeli pearl mussel. Japanese pearl farmers now culture a hybrid pearl mussel, which is a cross-breed between the last remaining Biwa Pearl mussels and a closely related species from China.

Freshwater Pearls from Lake Kasumigaura

The Lake Kasumigaura (Kasumiga-ura) region is a relatively new pearl cultivation area, started in the 1990s. Lake Kasumigaura, located 70 km northeast of Tokyo, in the Ibaraki Prefecture, is the second largest lake in Japan. Pearls cultured at the Kasumigaura Pearl Farm are known for their pink or rosy hues, and high luster due to a four-year cultivation period.

Pearls from the Lake Kasumigaura region are sold under the name of "Kasumiga Pearls" similar to the way in which Biwa pearls were branded nearly 100 years ago. For pearl cultivation, this region uses the Hyriopsis cumingi/Hyriopsis schlegeli, Anadonata/Plicata hybrid mussel, which is a cross between Japanese and Chinese pearl mussels.

Freshwater mollusks can produce significantly larger quantities of nucleated pearls (up to 50) than their saltwater counterparts, making them an ideal choice from a production standpoint. Akoya, or saltwater mollusks, will only tolerate a maximum of 4 to 5 nucleations in their gonad tissue. The Chinese are now using a 'saltwater culturing technique' on freshwater mussels, by nucleating freshwater mollusks with 'shell nuclei,' implanting in the mantle and body of the animal.

Pearls in Chinese Ceremonial Culture

The use of pearls, as a ceremonial object, in imperial funerary rituals dates back to the Qing Dynasty. In accordance with Imperial custom, a large pearl was placed into the mouth of the deceased to protect the corpse from decomposition.

The infamous Empress Dowager Cixi, also known as the "Dragon Lady" (1835 to 1908), who was the de-facto ruler of China during the Manchu Qing Dynasty, had a special fondness for pearls in life, and upon her death, a large pearl the size of a "robin's egg" was placed in her mouth. Her coffin was filled with pearls and other jewels, and placed into the Qing Tombs in Hebei Province, east of Beijing.

In 1928 the Empress Dowager's tomb was ransacked by Sun Dianying, a Kuomintang warlord. Cixi's body was desecrated, and it is rumored that some of her stolen jewels and her crown were given to Kuomintang leader Chiang Kai-shek who gifted them to his wife, Soong May-ling who used the pearls to decorate her party shoes.

Freshwater Pearl Characteristics

Freshwater pearls range from 4mm – 11mm in size. Only about 2% are spherical with 60% ranging symmetrical. (Ever wonder why freshwater pearls are more oval or button shaped?). White or cream bodycolor with hues of yellow, orange, pink and purple. Freshwater pearls can also show overtone of rosé, blue or green and some even show orient.

Most freshwater pearls are bleached then sorted by size, shape and color. Bleaching can dull the luster slightly so they are then placed in specially designed machines for tumbling. Freshwater pearls are sometimes dyed, usually black. Radiation is used to color-treat others. If in doubt about the color of the pearls, ask an expert to look for signs of treatment.

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