Although pearls are one of humanity’s most ancient gems, natural undersea beds of pearl-producing oysters now occur very rarely. Cultured saltwater pearls have become some of the most prized varieties of the traditional June birthstone.
Prices of pearls are based on several quality factors. The values provided in this guide are for round cultured pearls. Baroque pearls are about 25-35% the cost of round pearls.
Natural pearls are extremely rare, and largely limited to auction and collector’s markets. These can be worth 10 to 20 times an equivalent Akoya cultured pearl.
Creamy white to rose, silvery white, white with greenish hue, yellow, gray, black, black with metallic gray cast, bronze, green, blue. Pearls have body colors as well as overtones. See "Identifying Characteristics" below.
Found in the Atlantic, Indian, and Pacific Oceans, marine oysters from the genus Pinctada are the principal source of saltwater pearls, whether natural or cultured.
Gathering natural pearls is referred to as fishing, hunting, or pearling. Usually, divers gather these mollusks and remove the organic gems inside. Unfortunately, few wild Pinctada oysters yield pearls. (This is especially unfortunate for the oyster, which dies when taken from its home and opened in this fashion, pearl or no pearl).
For thousands of years, saltwater pearls have been highly prized for jewelry. The demand remains strong, though now it’s met almost exclusively through cultivation.
This Victorian 18k yellow gold brooch features a pear-shaped, natural saltwater pearl center stone surrounded by 2 rubies, 14 emeralds, 10 round pearls, and 15 rose-cut diamonds. The saltwater pearl is set on an agate carved like a clam shell. (The brooch also has a compartment that holds a lock of hair). Photo courtesy of liveauctioneers.com and SAJ Auction.
What’s the Difference Between Freshwater and Saltwater Pearls?
Although freshwater and saltwater pearls develop in different varieties of mollusks, they still form in the same manner. An irritant trapped in an oyster or other mollusk stimulates the production of nacre and the formation of the pearl.
Although both varieties share most of their chemical and physical properties, the marine specimens have historically set the standard of beauty for the appearance of all pearls. Natural freshwater pearls usually have more irregular shapes and poorer luster. However, with improved cultivation techniques, farmed freshwater pearls can now match their saltwater brethren in appearance.
Saltwater pearls have set the traditional standard for the round white pearl. However, natural pearls of any kind very rarely occur in perfectly round shapes. The natural saltwater pearls in this old European-cut diamond ring are notably off-round and somewhat asymmetrical when viewed from the side and bottom. Photo courtesy of liveauctioneers.com and Fellows.
Natural pearls may be inert to strong light blue, yellowish, greenish, or pinkish in both longwave (LW) and shortwave (SW) ultraviolet light (UV). Cultured pearls may have no reaction or the same reaction as naturals in LW.
Natural black pearls may be weak to moderate red, orangish red, or brownish red in LW.
Dyed black pearls may show variable reactions under LW but never the same as natural.
La Paz or Sea of Cortez pearls have a strong red reaction in LW.
Characteristics of Saltwater Pearls from Various Sources
Persian Gulf Pearls: Typically, creamy white or rose colors. Specific gravity (SG) is 2.68-2.74.
Gulf of Manaar Pearls: Typically, a pale, creamy white color, sometimes with fancy overtones of blue, green, and violet. SG 2.68-2.74.
Australian Pearls: Silvery white to yellow. SG 2.67-2.78.
South Sea Pearls: Usually, white color with little orient but also yellow, gray, and black, with a characteristic metallic, grayish cast.
Japanese Pearls: White, often with a greenish tinge. SG 2.66-2.76.
Venezuelan Pearls: Colors may vary from white to bronze, also black. White pearls may be very iridescent and almost glassy. SG 2.65-2.75.
California Pearls: Abalone, a group of shelled marine snails, may produce pearls of green, yellow, blue, and other tones. SG 2.61-2.69.
Grown in Pinctada fucata or Akoya oysters, Akoya pearls are the traditional cultured saltwater pearls. Raised primarily in Japan and China, their sizes typically range from 5 mm to 11 mm, though most are 5 mm to 7 mm in length. Usually, they have a white to cream body color but can occur in several other colors as well. If that weren’t enough, dyeing can turn Akoya pearls into any imaginable color. Unfortunately, pollution and illness have greatly impacted Japanese saltwater farms.
South Sea cultured pearls are grown in silver-lipped and gold-lipped Pinctada maxima oysters. Farms are found throughout the Indian and Pacific oceans, around Australia, Indonesia, Myanmar, and the Philippines. Larger than Akoyas, these pearls are usually 8 mm to 20 mm in diameter with white to gold body colors and low luster.
The famous Tahitian black cultured pearls are grown in black-lipped oysters, Pinctada margaritifera. Raised primarily in the waters of French Polynesia, they tend to be large like their South Sea cousins, ranging from 8 mm to 13 mm. These pearls have black or very dark body colors with prominent overtones of green and purplish pink.
Abalones produces both whole and blister pearls, usually green, yellow, or blue. Both the shell and the pearls are highly distinctive, with dark coloring and bright iridescence. A popular food item, natural abalones are becoming rare, especially on the California coast. Farms now raise them to meet culinary demands. In nature, the creatures grow to a foot or more in length. However, the farmed variety isn’t allowed to grow over 4”. If you have a shell over that length, you have a natural specimen for sure.
The world’s major pearl producing area, especially the coasts of Iran, Oman, and Saudi Arabia. For over 2,000 years, these waters have produced creamy white pearls. Persian Gulf pearls are usually small (less than 12 grains). During the diving season (May-September), hundreds of small boats work these waters. The diving depth is about 30′-90′ but usually less than 60′.
Pearls are recovered from oysters, washed, and then sold to merchants in Mumbai, India. Then, bleaching (using hydrogen peroxide and sun-light), sorting, grading, and drilling operations follow. In general, poor-quality pearls go to the Far East. Better pearls go mostly to Paris. From there, many reach the United States. Bombay is chiefly a brokerage center.
Historically, Persian Gulf pearls have been called “oriental pearls,” a term then used for all natural saltwater pearls. Today, the term “oriental pearls” refers only to natural Persian Gulf specimens.
Gulf of Manaar
An arm of the Indian Ocean, between Sri Lanka and India. An important source for more than 2,500 years, this area offers only sporadic fishing today. The Sri Lankan government controls the fishing and auctions the oyster haul. The oysters are opened by leaving them on the ground to rot. Then, people search the decomposed matter for pearls. Typically, the pearls go to Mumbai. Traditionally, the Gulf of Manaar produces pale, creamy white pearls.
Divers in armored suits fish for pearl oysters off the west, northwest, and north coasts. These produce silvery white to yellow pearls. Shell recovery is also a major industry, as important as pearl recovery.
The term refers to the South Pacific and Indian oceans, but these pearls are also generically called “Tahitian Pearls.” Native fisheries operate around Micronesia and Polynesia. These pearls may grow large and generally round, up to 7,100 grains. Tahiti is the major pearl center.
Japanese waters are rapidly becoming too polluted for the natural existence of Pinctada. Today, cultured pearls, typically white, constitute a much bigger industry.
Other notable or historic sources of saltwater pearls include the following locations:
United States, Florida and California: There have only been occasional finds in the US. They are mostly conch pearls and some abalone. California has produced some black pearls.
Mexico and Panama: Major sources until the 20th century, today they produce Tahitian-type cultured pearls. The Sea of Cortez also produces La Paz or Sea of Cortez pearls with colors unlike any other pearl.
Venezuela: Venezuelan oysters usually produce small pearls.
Red Sea: No longer a producing area, these pearls were famous for being whiter than most.
Sometimes, jewelers measure individual pearls in grains. One grain equals 0.25 carats. (Please Note: a grain as a unit of measurement has other values when used for other materials, such as gold).
The following are some of the most celebrated saltwater pearls.
“The Hope Pearl,” British Museum of Natural History (London). 2” long, 4.5” in circumference at the broad end, 1,800 grains. A saltwater pearl, possibly from Myanmar.
“La Pelegrina,” found near the Isle of Margarita, West Indies, 133.16 grains. Survived both the French and Russian Revolutions.
“La Peregrina,” found near Panama in 1560, 203 grains. Among its owners: Queen Mary I of England (“Bloody Mary”) and Elizabeth Taylor.
“The Gogibus,” found in the West Indies, 504 grains. Once the largest pearl known in Europe. Lost for over 300 years until it resurfaced in 2009.
“La Regente,” 337 grains. Purchased by Napoleon for Empress Marie-Louise.
“The Pearl of Asia,” found in the Persian Gulf in the 17th century, 2,420 grains. The largest known saltwater pearl in the world (excluding the “Pearl of Lao Tzu,” which is a tridacna pearl, a kind of calcareous concretion).
You can learn more about some of these as well as other famous pearls here.