Cultured pearls are genuine pearls created by a mollusk with human assistance. Unlike natural pearls, which form spontaneously, cultured pearls begin their growth through deliberate human action. Both are real and form through the same biological process within the mollusk.
The Nacre Formation Process
All pearls, whether natural or cultured, are formed through a biological process involving nacre, commonly known as mother-of-pearl. Nacre is a crystalline substance secreted by the mollusk’s mantle tissue, which lines the mollusk’s shell.
When an irritant, such as a parasite or a foreign object, enters the mollusk, the mantle tissue responds by enveloping it. The tissue then begins to secrete layers of nacre around the irritant. These layers build up concentrically, eventually forming a pearl. The continuous deposition of nacre provides the pearl with its characteristic luster and iridescence.
Initiating Cultured Pearl Growth
The creation of a cultured pearl begins with a precise surgical procedure known as nucleation. A skilled technician carefully inserts a small, spherical bead, typically made from a mollusk shell, into the soft tissue of a host mollusk. Alongside this nucleus, a small piece of mantle tissue, called a “saibo,” from a donor mollusk is also implanted.
The saibo is crucial because it contains the specialized cells that secrete nacre. These cells proliferate and form a pearl sac around the inserted bead. This sac then begins to deposit concentric layers of nacre onto the nucleus. The meticulous placement of both the nucleus and the saibo is important for forming a well-shaped pearl.
Cultivation and Harvesting
Following the nucleation process, mollusks are returned to their aquatic environment, typically suspended in nets or cages in controlled pearl farms. These farms are situated in protected bays or freshwater bodies, where water conditions, such as temperature, salinity, and nutrient levels, are carefully monitored. Mollusks require consistent care, including regular cleaning of their shells and relocation if water quality changes.
The time required for a pearl to grow varies significantly depending on the mollusk species and desired pearl size, typically ranging from one to three years. During this period, the mollusk continuously secretes nacre around the implanted nucleus. Once pearls reach their desired size and quality, mollusks are carefully brought to the surface, and pearls are extracted in a delicate harvesting process.
Major Types of Cultured Pearls
Different types of cultured pearls are produced based on mollusk species, geographic location, and cultivation techniques.
Akoya Pearls
Akoya pearls, primarily from Japan and China, are typically small, round, and white, grown in saltwater oysters.
South Sea Pearls
South Sea pearls, cultivated in Australia, Indonesia, and the Philippines, are larger with silver or golden hues, produced by oysters.
Tahitian Pearls
Tahitian pearls, known for their dark, exotic colors, are grown in oysters in French Polynesia.
Freshwater Pearls
Freshwater pearls, predominantly from China, are cultivated in freshwater mussels. They are often grown without a bead nucleus, resulting in a wider range of shapes, colors, and higher yields per mollusk.