China Pearls

Saltwater pearls from the Akoya oyster (Pinctada fucata martensii), which are usually cultured. These pearls are typically roundish, and their natural body colors normally range from light pink, to white, to yellowish. The chapters on pearl quality in this book focus on Akoya pearls.

Even though they are often called Japanese pearls, they can also be found in oysters outside Japan. In fact, China has become the major producer of Akoya pearls less than 7 mm in size. Korea, Hong Kong and Sri Lanka are already culturing pearls using the Akoya oyster. Currently, most Akoya pearls over 7 mm are cultured in Japan.

Pearls form within oysters, which live in the sea, and also within freshwater mollusks. Traditionally, most pearls were gathered from saltwater-dwelling oysters in the Persian Gulf, the Red Sea and the coastal waters of India and Japan, although China has harvested freshwater pearls for many centuries.

Saltwater pearls tend to be more lustrous than their freshwater counterparts, thereby increasing their desirability and value.

All saltwater pearls produced today are bead-nucleated pearls. Natural pearls are still collected in the Persian Gulf, but the yield is too small to account for any market value, and the pearls collected rarely leave the area.

Saltwater pearls are cultured by taking an oyster and prying it open a mere 2-3 centimeters. A technician then uses a special instrument to make a minute incision on the gonad (reproductive organ) of the oyster. A small nucleus is inserted into this hole, and a tiny piece of mantle tissue is placed behind it. The epithileal cells in this mantle tissue grow around the nucleus producing a pearl sac. This is where the pearl grows. This process is the same for all saltwater pearls cultured today.

The three most common types of saltwater pearls are Akoya pearls, Tahitian pearls, and South Sea pearls.

The Japanese, at Lake Biwa, are credited with being the first to succeed in cultivating freshwater pearls on a commercial basis, although freshwater pearls in the shape of Buddha had been cultured in China as far back as the thirteenth century. The technical roots of cultivating freshwater pearls are attributed to Masayo Fujita, the “father of freshwater pearl cultivation”.

The first harvest of Biwa pearls was in August 1925 and they had a shell bead nucleus like Akoya pearls. By the 1930’s they were being sold overseas. Some merchants from India would buy these Lake Biwa pearls from Fujita and then resell them to the Middle East as highly valuable Persian pearls for huge sums of money. One day, it was accidentally discovered that a shell bead is not necessary for the cultivation of a freshwater pearl. All that is needed is the insertion of a piece of mantle (a membranous tissue which secretes nacre and lines the inner shell surface of mollusks). This is a lot less trouble than inserting both a bead and mantle tissue. Also, it was noticed that after the first harvest, mussels can spontaneously grow pearls a second and third time. What this means is that cultured freshwater pearls usually have more pearl nacre than cultured Akoya pearls because most do not have a shell bead nucleus.

Pearls that are cultivated using just mantle tissue are called tissue-nucleated pearls in America and non-nucleated pearls in Britain and Commonwealth countries. When a shell bead is implanted along with a graft of mantle tissue, the resulting pearl is called a nucleated pearl or a head­nucleated pearl (The bead can be any shape; it isn’t necessarily round). The general term for any pearl cultivated in a lake, pond or river area is freshwater cultured pearl. For the sake of brevity, this book usually omits the word “cultured” since practically all pearls today are cultured.

Biwa pearls (pearls from Lake Biwa) have enjoyed a great deal of prestige. This is because they tend to have a smooth surface and a high, even luster. Unfortunately, production almost came to a halt in the early 1990’s due to the death of most of the Biwa mussels. It is now being resumed. Some dealers still have old stocks of pearls from Lake Biwa to sell, but many pearls which are identified as Biwa pearls are actually from China.

 Most freshwater pearls today are produced in China. Their quality has been steadily improving since 1991 and their sizes have been increasing. At the end of 1992, semi-round Chinese freshwater pearls made their appearance on the market and now offer an attractive, lower priced alternative to the round Akoya pearls. Some of the larger pearls are even becoming alternatives to South Sea pearls.

China and Japan are not the only places where freshwater pearls are found. There are many historical accounts about the natural freshwater pearls of Europe and North America. These pearls are still being sold, but in decreasing quantities. Overfishing, flooding and pollution has either dwindled or, in some areas, eliminated the supply of these natural pearls.

some people use the term “black pearl” to refer to any dark colored pearl, dyed or natural color. black pearls are not necessarily black. more often than not they rang from a light to very dark gray, but they may also look green, pink lavender, blue or brown. it is the oyster source, not color, that determines if pearls are called black pearls. “Black pearls” is a generic term that refers to pearls from:

Black-lipped pearl oysters(Pinctada margaritifera), Western to Central Pacific&Indian Oceans.

La Paz pearl oysters(Pinctada margaritifera), Eastern Pacific between Baja California&Peru.

Rainbow-lipped(western-winged) pearl oysters(Pteria sterna), Eastern Pacific between Baja California&Peru.

Some people mistakenly identify all black pearls as Tahitian pearls. Tahitian pearls are found in French Polynesia and they’re marketed in Tahiti. Pearls from the Cook Islands are Cook Island pearls, not Tahitian pearls. Black pearls from the Gulf of California can be called La Paz pearls, Mexican pearls, Baja California pearls or simply black pearls. Some sellers call black pearls from the rainbow-lipped oyster “rainbow pearls” because of their natural rainbow-like colors.

If you go to Hong Kong, you may see strands labeled “black pearls” that sell for a couple hundred dollars. They are probably artificially colored Akoya pearls whose natural color was undesirable. In Tahiti, “black pearls” must be of natural color to merit the name of “black pearl” or “Tahitian pearl.” The jewelers in both areas are correct in their use of the term “black pearl” as long as the treated pearls are identified as dyed, irradiated or treated black pearls. In other words, the unmodified term “black pearl” implies the pearl is of natural color.

Over 99.9% of the black pearls sold on the market today are cultured. So for the sake of brevity, this book often leaves out the term “cultured” when referring to cultured black pearls. Nowadays, when pearls are natural, they are identified as such. A few natural black pearls have been recently found in the Pteria sterna oyster off of Baja California. Natural pearls (those created without human intervention) are rare, so don’t expect to find them in your local jewelry store.

Natural-color black pearls can be confused with natural-color “blue pearls. ” Unlike black pearls, whose color is an inherent characteristic of the pearl nacre, blue pearls derive their color from foreign contaminants in the nacre itself or between the nacre and the shell bead nucleus. Naturally colored dark Akoya pearls are good examples of blue pearls. They may be blue, black, gray or brown. Black pearls and blue pearls can look the same but because of the difference in the origin of their color, blue pearls are worth less. The fact that blue pearls might decay or lose their color if holes are drilled through them is another reason for their lower value.

Since there can be a great value difference between black pearls, blue pearls and artificially colored pearls even though they may look the same, consumers need to be concerned about buying black pearls that are misrepresented. In Chapter 12, you’ll see how to spot pearls that are not true black pearls. Keep in mind, though, that the only sure way to identify a natural-color black pearl is to send it to a lab and have it tested.