Since their discovery many centuries ago, South Sea pearls have been among the most valued of all gemstones. Rings crafted with these gems have a tradition of representing love and commitment. Necklaces, bracelets, earrings, and other pieces of jewelry are often adorned with these beautiful beads. They are also used to decorate clothing, as well as the headpieces of royal family members.
There is no single global system for grading. However, these jewels are categorized by their surface quality, shape, luster, color and size. Large size, smooth surfaces, rainbow iridescence, deep luster and satiny finish are the most highly valued.
These tropical gems have natural hues ranging from cream, yellow and pink to silver, gold and white. The thick nacre linings inside the oyster shells create the pearl's rich iridescence. The beads are composed of many layers of nacre. Nacre is also known as mother of pearl, and is widely admired for its unique and captivating iridescence.
Only one type of oyster can create authentic South Sea gemstones. The large Pinctada maxima mollusk serves as host oysters for these elusive jewels. Their cousin, the Pinctada margaritifera creates black gems.
The elusive Pinctada maxima mollusks thrive in deep ocean habitats, as well as in farms. They are generally harvested from the waters of the Philippines, Australia, Indonesia and Tahiti. Only a small portion of wild Pinctada maxima oysters contain jewels.
Natural gemstones are collected from the wild. They are generally prized more highly than their cultured cousins, which are seeded and harvested on farms. The majority of today's beads are harvested from oyster-bed saltwater farms.
In the western part of Australia, the white-lipped and gold-lipped Pinctada maxima clams are primarily harvested. The black-lipped Pinctada margaritifera mollusks are harvested from the tropical seawater of Tahiti. The clams are named for the hues of their interior edges.
Growing up to 12 inches in diameter, the Pinctada maxima mollusks are the world's largest species of bead-producing oyster. Due to their size, they can create the world's largest gems, which can reach diameters of one-half inch. While the natural forms of these beads is irregular, cultured jewels are more commonly round.
Extending from the south tip of China to the north coast of Australia, the South Sea provides an ideal habitat for Pinctada maxima oysters. They are native to the seas of Australia, Tahiti and Fiji. The clear, warm tropical waters nurture deep layers of nacre, fast growth and large size.
In farms, the Pinctada maxima can be implanted with tiny beads or grains of sand when they are two years old. These implantations function as the seeds for new gems. The mollusks are returned to their saltwater habitat for two to three years for bead production. They secrete layers of nacre to entomb the seed, and form the beads. The oysters can survive the removal of the jewels. During their life-cycles, they can be reseeded about four times.
Centuries after their discovery by ocean traders, South Sea pearls remain highly valued. Their uniquely beautiful luster and iridescence make them one of the most desirable jewels in the world.