South Sea pearls are cultured pearls grown in the gold-lip and silver-lip pearl oyster, Pinctada maxima, the largest of the pearl oysters. Farms in northern Australia produce mostly white and silver pearls, while farms in Indonesia and the Philippines are best known for golden ones. These are usually the largest cultured saltwater pearls, commonly 9 to 16 mm, and their thick nacre gives them a soft, satiny glow.
The Pinctada maxima oyster
Pinctada maxima can grow a shell up to about 30 cm across, many times the size of the Akoya oyster used in Japan. A big oyster can carry a big bead, which is the main reason South Sea pearls are so large. It lives in warm tropical waters from the Bay of Bengal and Myanmar through Southeast Asia to northern Australia and Papua New Guinea.
The color of the shell's nacre varies. Silver-lip oysters have a silvery white rim inside the shell and tend to produce white and silver pearls. Gold-lip oysters have a golden rim and tend to produce cream to deep gold pearls. Farmers can steer pearl color by choosing donor tissue from oysters with the desired lip color.
The oyster has another advantage. Its nacre grows quickly in warm water, so it builds a thick coat over a bead in a reasonable time. Each round of growth usually lasts about two years.
Australia and Broome
Long before pearl culture, the waters off northwest Australia supported a large mother-of-pearl industry. From the late 19th century, the town of Broome in Western Australia became a center for pearl shell diving. Luggers worked the coast, and crews came from Japan, Malaya, the Philippines, Timor and Aboriginal communities. The shell was used for buttons and inlay, and any natural pearls found were a bonus. Diving was dangerous, with deaths from the bends, cyclones and accidents. Broome's Japanese cemetery holds the graves of hundreds of divers.
Plastic buttons collapsed the shell market after the Second World War. Cultured pearl farming began in the area in the 1950s, through a joint venture with Japanese technicians. Over the following decades, Australia became the leading source of large white cultured pearls.
Australia's industry has some unusual features:
- Most farms historically relied on wild-caught oysters, collected by divers from the seabed, along with hatchery-bred stock.
- The wild catch has been managed under a quota system to protect oyster stocks.
- The oysters live in strong tidal currents along a remote coastline, conditions that suit nacre growth.
Australian South Sea pearls are often white or silver with pink or blue overtones, and include some of the largest round cultured pearls produced anywhere. The page on mother-of-pearl covers the shell side of the business.
Indonesia
Indonesia's farms are spread across many islands, including Bali, Lombok, Sumbawa, Flores, Sulawesi and the islands farther east. Indonesia produces a wide color range, from white and silver to cream and gold. Its output rose steeply from the 1990s, and the country became one of the largest producers of South Sea pearls by volume. Hatchery-bred oysters supply much of the stock.
The Philippines and golden pearls
The Philippines is closely tied to the golden South Sea pearl. Farms on Palawan and in the southern islands, among other areas, use gold-lip oysters to grow pearls with strong golden color. The South Sea pearl is the national gem of the Philippines, a status set by presidential proclamation in 1996.
Natural golden color in these pearls is rare in its deepest shades. Some golden pearls on the market are dyed or color treated, so a lab report is worth getting for a high-priced golden pearl. Natural golden color tends to look warm and even, while dyed pearls can show color concentrations in drill holes and blemishes. The gemstone treatments page covers disclosure.
Myanmar has also produced South Sea pearls from Pinctada maxima in the Mergui Archipelago, though its output has been smaller.
How South Sea pearls are grown
South Sea farming follows the bead nucleation method described on the cultured pearls page, with some differences:
- A large bead goes in with a small piece of donor mantle tissue, typically one pearl per oyster.
- The oysters live in panels hung from longlines or rafts. Workers turn and clean them regularly so the pearls grow evenly and parasites stay under control.
- Harvest comes after roughly two years of growth.
- A healthy oyster that produced a good pearl can be nucleated again with a larger bead in the same pearl sac. Some oysters go through three or more rounds, each yielding a larger pearl.
The long growing time, the size of the oysters and the remote farm locations all raise costs. Many oysters die or reject their beads, adding to the expense.
Size and nacre
South Sea pearls usually start at about 9 mm, and pearls between 10 and 15 mm are common in the trade. Pearls over 16 mm exist but are scarce, especially in round shapes. Their nacre is typically thick, often 2 mm or more, compared with much thinner coats on many Akoya pearls. The thick nacre and the fine platelet structure give South Sea pearls a deep, soft luster, more satiny than the sharp shine of a fine Akoya.
Shapes run from round and near-round through drops, ovals, buttons and circled pearls to baroque. Round pearls are a small part of each harvest and cost the most. The pearl grading page explains how shape, size, luster and surface trade against each other.
South Sea compared with Tahitian
| Feature | South Sea | Tahitian |
|---|---|---|
| Oyster | Pinctada maxima | Pinctada margaritifera |
| Main sources | Australia, Indonesia, Philippines | French Polynesia |
| Typical colors | White, silver, cream, gold | Gray, green, blue, purple, near-black |
| Typical size | About 9 to 16 mm | About 8 to 15 mm |
The black-lip oyster that produces dark pearls is covered on the Tahitian pearl farming page. The overview on pearls compares all the main pearl types.
Frequently asked questions
Why are South Sea pearls so expensive?
The oysters are large, slow to raise and usually carry one pearl at a time for about two years. Many fail, and farms are remote, so each good round pearl has a high production cost.
Are golden South Sea pearls natural in color?
Many are, especially those from gold-lip oysters in the Philippines and Indonesia. Some golden pearls are dyed or treated, so a lab report helps for important purchases.
What is the difference between South Sea and Akoya pearls?
South Sea pearls come from the much larger Pinctada maxima oyster, so they are bigger and have thicker nacre. Akoya pearls are smaller, with a sharper, more mirror-like luster.
Where do the best white South Sea pearls come from?
Australia has the longest reputation for large white and silver South Sea pearls. Indonesia also produces fine white pearls.