By Elisabeth Strack
Pearls have been admired and cherished since ancient times. They were highly appreciated in Greek and Roman antiquity, and ever since, they have enjoyed a positive reputation as objects of adornment and value, sourced from various locations around the world.
There still exist a number of natural pearl sources that have been known for centuries. Interestingly, no new discoveries of these locales have been added since; any developments on this front instead refer to cultured pearls (with the exception, perhaps, of those rare exotic natural pearls that come from gastropods and mollusks other than the conventional bi-valves of the Pteriidae family, which have attracted market attention only in recent years). Nonetheless, it stands to reason an update on pearl localities is necessary if you intend to sell or work with these historic precious objects.
Birthplaces of natural pearls
Most Oriental pearls are still sourced from traditional localities in the Persian Gulf and the Red Sea, known since antiquity, that are, from a European point of view, toward the east (Figure 1). These pearls rarely exceed 7 mm (0.28 in.) and mainly originate from the small Pinctada radiata species, which has a length of approximately 80 mm (3.15 in.).
In the 15th and 16th centuries, the discovery of new sea routes, both to the east and to the west, led to additional pearl localities. Indeed, while on his third voyage to the Americas in 1498, Christopher Columbus came across pearls on the coast of present-day Venezuela. Soon after, more pearl banks were discovered in both the western Atlantic zone and along the Pacific coast. The new pearls, once referred to as ‘Occidental,’ originated both from the same small Pinctada species as Oriental pearls, and from the Pinctada mazatlanica species which delivered larger, darker pearls. Alas, the banks no longer exist today.
While natural pearls have consistently maintained high value (even amidst the Great Depression) and moved on a different level from cultured pearls, the past 15 years have seen a distinctive rise in prices of fine qualities, reaching price levels close to those seen in the pearl trade’s historical blossoming period between 1850 and 1930.
‘Exotic’ natural pearls
While largely confined to a small international market of connoisseurs, the renewed demand for natural pearls can, perhaps, be indicative of a new ‘prime time’ to come. Likewise, it may explain the sudden interest in ‘exotic’ pearls, originating from either marine gastropods or other non-Pinctada bi-valve mollusks. Contrary to those from Pinctada, however, exotic pearls usually have a non-nacreous structure.
While pink conch pearls from the Caribbean gastropod Strombus gigas saw significant favour in the art nouveau period, prices sky-rocketed only in the years after 1995 (Figure 2). Lately, pearls similar in appearance have emerged from the so-called ‘horse conch’ (Pleuroploca gigantea) from Mexico’s Baja California.
Likewise, individual examples of bluish-green abalone pearls (Haliotis genus) and orange melo pearls (Melo genus) had been known before the 19th century, but only attracted attention (and demanded high asking prices) in the 1990s. Abalone pearls are mainly found in California, while melo pearls—which are among the most expensive natural pearls on the market—originate in the South China Sea and the Mergui Archipelago.
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Turbo (Turbo marmoratus) and Cassis (Cypraecassis rufa) pearl varieties, while known for many years, only recently made an appearance on the market.
A complete novelty are pearls from Tutufa bubo (Figures 3 and 4)—or ‘the giant frog snail,’—a gastropod occurring in the Red Sea and the Indo-Pacific Ocean.
Non-Pinctada bi-valve mollusks
At one point, pearls originating from outside the Pinctada genus were regarded as oddities; however, this attitude has shifted in the past two decades toward seeing these as expensive rarities.
Some examples of these varieties found in Baja California include the reddish-white lion’s paw pearls (Figure 5), which are found in the scallop Lyropecten subnodosus; black Atrina pearls from a pin shell of the Atrina genus; and spondylus pearls from the spiny oyster (Spondylus princeps, Spondylus calcifer).
Additionally, quahog pearls from the Venus clam Mercenaria mercenaria are abundant in New England. Known locally as quahog shell, these varieties are reminiscent of the colourful ‘wampum’ shells once used by Indigenous peoples.
Finally, white Tridacna pearls in sizes greater than 14 mm (0.55 in.) come from the giant clam Tridacna gigas, found in the Pacific Ocean.
In Europe, there is no longer production of freshwater pearls, as the European pearl mussel Margaritifera margaritifera is under protection and has largely disappeared. Today’s market concentrates on freshwater pearls from the United States, which still occur in a variety of shapes and natural colours.
American pearls experienced their heyday during the ‘pearl rush’ of the late 19th and early 20th centuries. This era saw a sometimes frantic search for pearls in nearly all of the states along the Mississippi River, where about 30 species of freshwater mussels were found to produce pearls regularly.
In the 75 years that have passed since the end of World War II, the Japanese cultured pearl industry has undergone a number of significant changes.
Following a climax in the ‘60s (one which saw yearly production between 70,000 and 90,000 kg), a severe crisis occurred in the ‘90s that saw annual production fall to about 15,000 kg. Recent years have seen an emphasis on natural colours while the traditional Akoya market still enjoys conventional white pearls as large as 10 mm (0.39 in.) with a high nacre thickness and a pink overtone.
Since the ‘90s, Vietnam has also produced Akoya cultured pearls with very good nacre thickness at a high rate. Conversely, China no longer plays a role in this market. Indeed, attempts to establish Akoya pearl farms in the Persian Gulf, the Red Sea, on the coasts of India and Sri Lanka, and even on the eastern coast of Australia, using local Pinctada species, have so far not achieved regular production.
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It was only after eastward sea routes were established in the 16th century that pearls larger than 10 mm (0.39 in.), originating from the sizable Pinctada maxima, became recognized from localities between the Indian and Pacific Oceans. Already known to Renaissance goldsmiths, these pearls were famously used in 18th century grotesque figurines.
The large shells of Pinctada maxima, which measured up to 300 mm (12 in.), were well suited for the mother-of-pearl industry of around 1900. It was out of this industry’s established structure that cultured pearl production developed in Burma, Indonesia, the Philippines, and, from the late ‘50s onward, Australia. These individual countries have since become independent producers of the large South Sea cultured pearls.
Further, Australia still excels in the production of white, round, perfect pearls. This is thanks, in part, to highly sophisticated levels of grafting and farming technologies (which also offer the added bonus of keeping the environment intact). Interestingly, Pinctada maxima that occur south of the equator tend to have white shells (dubbed the ‘white lip’) and, accordingly, its pearls tend to be white. Meanwhile, when formed north of the equator, the ‘gold lip’ is more frequently encountered, producing golden pearls. The leading country for high-quality gold pearls is the Philippines, while Indonesia produces both white and golden pearls.
Tahitian cultured pearls
In the late ‘70s, black cultured pearls produced in French Polynesia with Pinctada margaritifera cumingii (the black-lipped variety of the Pinctada margaritifera species) appeared on the market. These demonstrated a variety of blackish hues, interspersed with various overtones, with sizes ranging from 8 to 18 mm (0.31 to 3.15 in.).
Dubbed ‘Tahitian cultured pearls,’ prices for this variety rose and, by the late ‘80s, they surpassed those of white South Sea cultured pearls. Prices have since decreased considerably, as the industry underwent a number of changes—ones that can best be summed up as repeated efforts by the government to exercise control with regard to farming techniques, quality requirements, export regulations, and marketing strategies. Roughly half of the production is exported to Hong Kong, where the Tahitian Pearl Association Hong Kong (TPAHK) actively supports publicity campaigns. As such, the past five years have seen an upward trend in prices for good qualities, leading to a stable market.
Other pearl culture in the Pacific Ocean
The nation of Cook Islands was quite successful in the ‘90s with its local Pinctada margaritifera cumingii species; however, the country has since lost its top spot for production to Fiji. This is largely due to J. Hunter Pearls Fiji, which produces large quantities of lustrous, large, and intensely colourful pearls. The company has also been praised for its sustainable farming efforts.
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Meanwhile, on the eastern side of the Pacific Ocean, Mexico has become another successful producer. Since ‘95, marine biologists from Perlas del Mar de Cortez, a wholesale producer near Guaymas, have achieved a regular production of intensely colourful pearls from Pteria sterna (a species related to Pinctada).
Freshwater cultured pearls
China first gained publicity for its cultured pearls in the second half of the 20th century. These pearls had irregular shapes, as they were produced without a mother-of-pearl bead by inserting tiny pieces of mantle epithelium from a donor mussel. Mass production followed and, in the ‘80s, pearls (often artificially dyed) were sold by the kilo.
The quality of these pearls saw further improvement in the early ‘90s when farmers started to use the Hyriopsis cumingii mussel; shapes became more round, and pink, purple, and orange natural colours were produced.
Further still, by 2000, new techniques had been introduced for inserting mother-of-pearl beads into Hyriopsis cumingii or hybrids of the Chinese Hyriopsis cumingii and the Japanese Hyriopsis schlegelii mussels. One method made use of already existing pearl sacks on both sides of the mantle, which were inserted with beads. An alternative technique, referred to as the ‘in-body’ method, inserts a drilled mother-of-pearl bead into the mussel’s gonad. While both options deliver large, colourful pearls of baroque shapes, those produced using the latter technique are more expensive, as only one or two pearls are grown at the same time.
China remains the largest producer of freshwater cultured pearls. A variety of prices exist side by side, ranging from artificially dyed low quality, to quite decent roundish or baroque shapes, to perfectly round fine qualities. Recent years have seen a decrease in production, with an added concentration on improved qualities accompanied by slight to pronounced price increases.
Since ‘93, Japan has a small production of high-quality pearls from Lake Kasumigaura, produced using the ‘in body’ method (Figure 6). These pearls, available in sizes of up to 15 mm (0.59 in.) have intense purplish to pink and orangey hues.
Additionally, since 2010, similarly intensely coloured pearls, dubbed ‘Edison pearls’ have been produced by the Grace Pearls Jewellery Company of China.
Culturing exotic pearls
Attempts to produce cultured Abalone pearls have been underway in several countries since the ’90s with some success. New Zealand’s Eyris Blue Pearls, for example, has produced mabe pearls. Additionally, a pilot project has recently been announced from Chile. Meanwhile, only one project for producing Conch pearls has become known, announced in Florida eight or nine years ago. Thus far, no regular production has been achieved.
Elisabeth Strack is a German gemmologist who has owned her own diamond, gem, and pearl testing laboratory in Hamburg since 1976. She is the author of the book Pearls, which was published in English in 2006. Strack can be reached via email by contacting email@example.com.