The Hidden Beauty: How Are Natural Ocean Pearls Created?

The countless shells scattered along the seashore are merely the outer coverings of soft-bodied sea creatures known as clams. These clams secrete a congealing slime from special glands in their bodies. This slime transforms into the shell that we know as the clam shell.

There are about 7,000 known species of clams in the world today. They thrive mainly in tropical and temperate regions, residing in shallow waters or at depths of thousands of meters below sea level. Some of the tiniest measure only a few millimeters, while the largest can reach up to a meter in diameter, weighing between 220 to 330 pounds.

Among these, the "pearl oyster" holds significant economic value, producing the pearl within its body. The pearl claims the title of the first gemstone ever discovered. Unlike other precious metals and stones that required polishing, pearls emerged with natural beauty needing no enhancement. Throughout history, pearls, growing within a living sea creature, were both mysterious and rare, sparking immense curiosity. In ancient times, they were of immense value, affordable only to the wealthy, symbolizing affluence and luxury.

A Well-Kept Secret

Finding a natural pearl was once exceedingly rare, as only 1% of collected oysters yield a pearl. It could take years to gather enough for a single strand of pearls. This rarity led to endless attempts throughout the ages to unravel the secret of pearl formation, aiming to reproduce it bountifully. Yet, the mollusk kept its secret, nestled within its locked shell.

It was the Japanese who discovered the secret, paving the way for the first cultured pearls. The breakthrough came when three Japanese individuals, each working in separate laboratories, found that secretions from the oyster's mantle formed the pearl. Through experimentation, they induced the oysters using various materials, and astonishingly, their oysters "birthed" round pearls. After centuries of mystery, the puzzle was finally solved.

The Discovery of Pearl Fertilization

Today, it is known that natural pearls form when an irritant, like a shell fragment or a grain of sand, finds its way into an oyster. This stimuli prompts the oyster's mantle to grow a "pearl sac" and start secreting nacre, which forms the pearl.

Out of the three Japanese pioneers, Kokichi Mikimoto gained fame for his discovery. After years of trials and extensive research, introducing various stimuli into oysters, he discovered the first clue and, in 1908, patented the world's first round cultured pearl. Mikimoto established a major cultured pearl business, at one point controlling over 12 million oysters, accounting for about 75% of the world's pearls.

Artificial Fertilization

Cultured pearls are borne from an intense and meticulous process. Oysters are carefully collected and selected, then undergo a precise and delicate nucleus implantation. They grow under strict conditions for several years. Numerous factors can kill the oyster or damage the pearl within, meaning every condition is considered—from the type of water (fresh or salt), water quality, temperature, time submerged, cleanliness, and other potential threats.

The initial stage in pearl cultivation involves artificial fertilization of oyster eggs. These eggs are cultured in a controlled water environment until ready (15 to 25 days). They are then collected and grown in nets under close supervision in seawater until mature at the end of two or three years. After this period, they are harvested, selecting healthy "mother oysters" capable of producing quality pearls. As the oysters grow and become mother oysters, the size of their nets changes. To prepare a mother oyster for nucleus implantation, the oysters are tightly packed, subjecting them to respiratory challenges. This slowdown in their physiological function helps them withstand the shock of nucleus implantation.

Inside the two halves of the oyster shell lies a tissue called the "mantle." This mantle encases the oyster's internal parts and filters the vigorous water flow. It is the only part of the oyster that can secrete nacre. Through its reproductive process, the mantle secretes nacre in response to the stimulus provided by the implanted particle.

The particle inserted in the pearl processing is a piece from a mother-of-pearl shell, typically sourced from Mississippi River pearl oysters in the United States. It was determined that this shell particle is best suited for pearl reproduction due to its composition, which is nearly identical to a pearl’s and thus not foreign. Attempts to create similar particles from alternative materials, like plastic or stone, failed to yield successful results. This particle is crucial to the enigmatic formation of the pearl, hence the importance of sourcing it from a healthy shell.

The Seeding Process

The pearl seeding process is a slow, gentle procedure, akin to surgical implantation. The oyster will die if the mollusk inside is harmed. Initially, the oyster is carefully opened slightly, and a small wedge is inserted to continue the "operation." An incision is made in the "foot" of the mollusk, into which the particle and a pre-prepared piece of mantle tissue, of the same size as the particle, are implanted. Post "operation," the oysters heal and are relocated to areas near open sea, housed in wire cages. There, conditions resemble their natural habitat more closely, though they face many dangers. One of the critical components for cultivating quality pearls is maintaining vigilance over the oysters throughout their water dwelling, shielding them from all natural disasters possible.

One of the foremost tasks is cleaning the oysters. Various organisms, like other clam species, algae, or sea grass, adhere to the cultivation basket, obstructing the oyster’s best water circulation, eventually weakening them. During pearl cultivation, they require cleaning at least ten times. Oysters are also highly sensitive to water temperature, which makes winter a potential threat. By late fall, they're moved to warmer waters, sustaining them until spring.

Another threat facing the oysters is typhoons. The heavy rains and violent winds that accompany typhoons can whip the pearl rafts away from shore. Those engaged in the pearl industry must be prepared for such weather, often venturing out in turbulent and hazardous seas. Despite vigilant care, about half the oysters perish during cultivation. Consequently, the pearls that do survive must largely be of exceptional quality. Pearls are collected in winter, the season they’re at their most beautiful, yet, as noted, not every oyster returned from nature contains a pearl...

What's the Cost?

Japanese cultured pearls have significant value and are exported worldwide. Their esteemed status in the market is largely due to the advanced technology and techniques used in pearl jewelry creation by the Japanese.

The global pearl market operates from the end of December to February, aligning with the "pearl harvest" season. Various pearls, from the best to the poorest, are displayed in containers by size, allowing buyers to examine their quality before making an offer. Pricing is determined by weight.

Like diamonds, pearls undergo price appraisal. Beyond the extensive variety of genuine pearls (both natural and cultured), many imitations—such as plastic or glass—exist. Certain objects develop within different clams and shells, mimicking pearls in appearance but lacking the real pearl's composition. Beyond this, a pearl's value can be measured by five factors: luster, surface quality (smooth or blemished), shape, color (the black pearl being the rarest and most costly), and size.

Pearls can be inspected through X-ray and magnification. Fake pearls may closely resemble real ones in shape, color, and shine but lack the characteristic layered structure, appearing excessively smooth upon slight magnification.