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Pearls: How They are Formed

October 27, 2011

Many world cultures hold myths about the moon and the origins of pearls: pearls are formed when dewdrops filled with moonlight drop into the sea to be eaten by oysters, the moon bathes in the ocean and attracts oysters to fill with dewdrops, or pearls fall from the sky when dragons fight. One famous pearl is named “The Pearl of the Moon” and was found in the Arab Gulf in 1550. It was a revered treasure of the Chinese Empire, all 309.89 carats of it!

 Of course, pearls aren’t dewdrops impregnated with moonlight, even though that is an apt description of their luminous appeal. They happen in a much less poetic manner. Pearls are formed within a living creature as a way of protecting it from invasive matter. Oysters are the mollusks we typically associate with pearl formation, but others produce pearls, too. Mussels and clams are bivalve mollusks that make pearls. Abalone is a univalve sea animal that creates an exquisite pearl, but rarely.

Oyster

 A bivalve is a sea creature whose shell has two halves or valves with a ligament that connects them and keeps them opened enough for the mollusk to feed. As a baby oyster grows, so must its shell. An organ within the oyster or mussel, the mantle, uses minerals from its meal to grow the shell. It does this by producing nacre, also known as mother-of-pearl, the shimmery inner lining of the shell.

 Nacre also comes into play when a foreign substance slips between the mantle and the shell and irritates it. Although, the story that a pearl can be produced by a grain of sand is an exaggeration. The offending matter needs to be larger than that to trigger the organism’s natural response, which is to encapsulate the irritant in a pearl sac and cover it with layer upon layer of nacre to relieve discomfort. Over time, a pearl is born. Nacre is a translucent substance; light shines through the surface of the pearl and creates the glow that is characteristic of these jewels from the sea.

 The creation story of a cultured pearl is somewhat different from these naturally occurring pearls in that an irritant is purposefully inserted in the mantle of the host mollusk. The Japanese were experimenting with pearl culturing as early as the 13th century, but only semi round or blister pearls were formed out of their efforts. Spherical pearls were successfully cultured in the early 20th century using a delicate process perfected by a Japanese noodle maker, Kokichi Mikimoto.

 Today the preferred process for culturing round pearls in saltwater oysters consists of inserting a round nucleus into the connective tissue of the oyster. Pearls from the Akoya oyster–Akoya pearls–are considered to be the classic round pearls, possessing renowned luster. The cultured pearl industry really took off with the successful production of pearls using freshwater mussels rather than saltwater oysters. The mussels are implanted with pieces of mantle tissue from other mussels and the nacre secretion process begins. They don’t require the addition of a nucleus to stimulate the pearl making process.

 One of the original sites for freshwater pearl culturing was Lake Biwa in Japan. The first commercial pearl crops were harvested there in the 1930’s. The Biwa pearls had color and luster not seen in saltwater cultured pearls, and they were solid nacre.

Biwa Pearls - JCD "Sticks and Stones" earrings

 China entered the cultured pearl scene in the 1960’s, as the Japanese industry waned due to extreme pollution of the waters. The early Chinese freshwater culturing efforts were ridiculed. These seed pearls were likened to rice krispies! But by the 1990’s, the Chinese had become the masterful pearl producers. Their experimentation with bleaching and dying pearls, as well as their creation of an incredible range of pearl shapes and sizes, has changed the face of the pearl forever. The perfect round beauty now has flat, rectangular, and potato shaped members in its extended family!

 Although cultured pearls are equally as beautiful as naturally occurring ones, they are much less expensive because they are readily available. Now moonlight dropped into the sea can be captured by anyone.

"Mandarin Moon" - Mabe and Potato Pearls

Pearls: A Brief History of Naturally Occurring and Cultured Pearls

October 16, 2011

Since the discovery of the first naturally occurring pearl, perhaps by seaside hunter gatherers in a perpetual search for food, pearls have been on a journey from obscurity to the quintessential “have-to-have” in every woman’s jewelry box.

 Pearls weren’t found in every bivalve mollusk our ancestors popped open for the sweet meat inside, but they would have come across them intermittently. A little knowledge of the power of intermittent reinforcement tells us that pearls probably acquired a “sought after” reputation. In this time before recorded history, pearls may have become a treasured byproduct of the quest for food. It seems a good place to start the pearl’s junket to the jewelry box.

 Considering three or four perfect pearls can be harvested from a ton of oysters, it’s easy to see how pearl ownership remained the domain of the rich for centuries. Free-diving pearl hunters dove to depths of up to 100 feet to manually open the mollusks in search of the elusive pearl. Today the sea women–Ama–of Japan still dive holding their breath, not taking advantage of the diving gear invented in the early 1900’s. From Caesar and Cleopatra to Anne Boleyn and Mary Queen of Scots, naturally occurring pearls were worn with pride solely by the privileged until the arrival of another invention of the early 1900’s.

 Independently of one another, three Japanese men–a carpenter, a noodle maker, and a government biologist–figured out ways to get oysters to produce round pearls on demand by introducing an irritant into the mollusk’s mantle or body. Freshwater mollusks had been coaxed into pearl production for some time, but the pearls produced were mabé, pearls that grew against the inside of the oyster shell and, therefore, weren’t round. Each of the three men held patents, but the noodle maker, Kokichi Mikimoto, and his Akoyo pearl prevailed. He is credited with bringing pearls within reach of common folk worldwide.

Rainbow Mabé pearl earrings, 13/16" diameter with unique post/clip closure

 By the 1920’s, virtually anyone who wanted to could twirl a long strand of pearls while dancing a Charleston. After WWII, single strands of pearls became the classic accessory for Grace Kelly and everybody’s mom and grandmother, as GI’s brought Akoya pearls home from Japan. Coco Chanel raised pearl wearing to a new level and showed women how to drape and layer pearl strands of different lengths and pearl size. In the 1960’s, tiny seed pearls gained renewed popularity, having been the the source material for intricate and romantic creations a century earlier. And, today’s brides search for a traditional pearl creation that will be as meaningful to them as Krishna’s gift of pearls was to his daughter on her wedding day.

 The rich and famous will continue to own the rarest pearls: Richard Burton gave Elizabeth Taylor La Peregrina, one of the most celebrated pearls in existence, and Jackie Kennedy was gifted a strand of rare, yellow Margarita pearls by the president of Venezuela. Princess Diana commissioned a gown to wear on a state trip to Hong Kong in 1989. It was completely covered in pearls, hand embroidered in place. Equally precious now are the heirloom pearls everyday people add to their jewelry collections everywhere to pass on to those princesses and first ladies everyone knows.