Rapaport Magazine
Colored Gemstone

Carribean Queen

Porcelain-like with a silky glimmer and, at their finest, an iridescent flame pattern, conch pearls are fascinating designers and consumers alike.

By Deborah Yonick
Like a fine gemstone that combines a distinctive appearance with rarity, the conch pearl is beginning to capture the attention of the U.S. market. Consumers here have been slowly warming up to conch pearls, according to Daven Sethi, expert in natural conch pearls for the New York–based pearl company, Tara. “In America, the market has only recently started to grow for this rare gem,” he explains. “As conch pearls get more exposure, demand is expected to rise. We’ve seen interest increase when we’ve displayed these gems at retail events. In Europe and Asia, demand is greater for conch pearls primarily because consumers there know the history and understand the uniqueness and rarity of these gems.”

The appeal of conch pearls to the designers who are discovering them is their huge variety of colors, shapes and variable surface patterns, along with their china-like luster, weight and hardness in comparison to other gemstones.

“I seek out conch pearls to work with whenever I can because they’re so rare to find, making them so special to put together a necklace, ring or pair of earrings,” says Los Angeles–based designer Cynthia Bach. “As a designer, I love to work with gems that are out of the ordinary, the more rare and unusual, the better.”

Conch Characteristics

The byproduct of the commercial harvest of conch meat, conch pearls are produced by the biggest sea snail, the queen conch or Strombus gigas, and are found from the Spanish Main north to Bermuda. Experts say that one in 10,000 conch shells produces a pearl, and two or three of every 100 pearls will be really special.

Conch pearls look different than nacreous pearls from saltwater oysters and freshwater mussels, whose flat, aragonite crystals are layered with membrane-forming protein to form conchiolin or nacre. Their reflective surface is known for its unique play of light called orient. Non-nacreous pearls from sea snails and giant clams, on the other hand, have a matte luster akin to ceramic.

Unique to conch pearls is an arrangement of crystalline calcite in concentric layers that interacts with light to create a changeable, sometimes undulating, luster or glow across the surface of the pearl known as chatoyancy, found in minerals like cat’s-eye chrysoberyl. Not classified as “true pearls” because they are not nacreous, some conch pearls still display a spectacular sheen that rivals the luster and orient of fine nacre pearls, according to Susan Hendrickson, marine archaeologist and conch pearl expert currently based in Honduras.

Heavier than other pearls with their specific gravity of 2.85, conch pearls also are tougher, with a median 5 on the Mohs scale of mineral hardness. They come in colors — including pink, cream, gold, brown and white — that are influenced by the algae the conch consumes. Depending on the shape of the irritant and the movement of the conch, the final form of the pearl is commonly baroque, the most desired shape is spherical and other possibilities are oval, teardrop and triangle, explains Manuel Marcial de Gomar, conch pearl dealer and owner of Emeralds International, Key West, Florida. In terms of size, conch pearls typically range from 2 carats to 6 carats, with 8 carats to 12 carats extremely rare.

Bach notes that it’s very difficult to find a single pearl that is symmetrical and also has a prominent flame pattern. She particularly loves the porcelain sheen and sherbet colors of this unique gem, which her sophisticated clientele have embraced.

Size, shape, color and the quality of the flame pattern on its surface are all variables used to determine conch pearl prices. Sethi notes that the quality of the flame can cause a huge variance in price and de Gomar cites double cat’s-eye conch pearls fetching $6,500 to $7,000 per carat.supply and demandCouture designer Paula Crevoshay of Albuquerque, New Mexico, says she has found a steady supply of conch from the Caribbean in 3-mm to 15-mm sizes, with strong demand for good quality. She notes that pure white conch from the Sulu and Celebes Seas, while rare, can be found in larger sizes up to 20 mm.

“Prices for nice Caribbean conch range from $1,000 to $3,000 per carat, while top grade from the Celebes Sea can reach $5,000 a carat,” Crevoshay says. “The challenge is to find top-quality pearls that have not been worked and that possess lab certification. Most of the pearls on the market are of low quality, with poor luster, no flame and irregular shapes.” But de Gomar argues that even lesser-quality material sells, with commercial-grade conch pearls available at retail for about $200 per carat.

Bach, who began working with conch pearls about four years ago, says she deals directly with divers in the Caribbean, specifically for her supply of conch and melo-melo pearls.

Ironically, the growing demand for conch pearls comes at a time when its supply is threatened and its harvesting is increasingly regulated.

Hendrickson notes that just three decades ago, queen conches dotted the ocean floor from the Yucatan, along the Cuban coast and Florida Keys, eastward through the Caribbean basin as far as Barbados and north into the Atlantic Ocean to Bermuda. “When conch meat became a popular delicacy, trawling hunters moved in and turned the conch lands off of North, Central and South America into killing fields, forcing all but three conch-producing countries to ban or sharply limit queen conch gathering,” she says.

The stocks of the Strombus gigas already are drastically reduced in the Caribbean, says de Gomar, and supplies everywhere have been impacted by pollution and overfishing. In 1992, the Strombus gigas was identified as a commercially threatened species by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), an international agreement that provides varying degrees of protection to more than 30,000 species of animals and plants.

Under the auspices of CITES, some countries have initiated restoration efforts that include relocation of adult conches and the establishment of marine-protected areas and aquaculture for the recovery of stock. In addition, countries have imposed their own fishing bans, quotas and regulations, including a minimum size for shells retrieved, to protect stock until the population recovers.

Future

Due to the limited supply of natural conch pearls, it’s not surprising these gems are imitated. “One way is by carving conch shells into beads, which produce a flame structure common to the shell and natural pearl, but also a layered structure common only to the shell, making these copies easy to identify,” says Kenneth Scarratt, managing director of the Gemological Institute of America (GIA) for Southeast Asia and director of the GIA Laboratory Bangkok. “Pink coral has been cut to imitate conch pearls also, but they, too, are simple to spot, given their different growth structures.”

For more than 25 years, attempts at culturing pearls from the queen conch have been unsuccessful, due to the animal’s sensitivity to traditional pearl seeding techniques and its spiral-shaped shell that makes it nearly impossible to reach the internal pearl-production area without endangering the animal’s life.

In the fall of 2009, Drs. Hector Acosta-Salmon and Megan Davis from Florida Atlantic University’s Harbor Branch Oceanographic Institute announced their success in producing beaded and nonbeaded cultured pearls from the queen conch in an aquaculture facility. “Perhaps the most significant outcome from our research is that the technique we’ve developed does not require sacrificing the conch in the process,” Davis says. “The 100 percent survival rate of queen conch after seeding and the fact that it will produce another pearl after the first one is harvested will make this culturing process efficient and environmentally sustainable.”

GIA Laboratory Bangkok examined more than 200 cultured conch pearls produced at the Florida facility. Samples were spherical, oval, elongated oval and irregular shapes, in sizes from 1 mm to over 10 mm, and more than 10 percent showed good luster and flame.

Raman spectroscopy and scanning electron microscopy revealed that all the cultured pearls were composed of aragonite fibers in bundles with alternating orientations — identical to that seen in natural conch pearls. But Scarratt says x-radiography clearly shows the beads or tissue-related cavities in the pearls.

Once cultivated pearls such as these enter the market, says Sethi, the prices and value of the natural pearl will increase dramatically, as has been the case with other natural pearls when cultured varieties became available.

 

Article from the Rapaport Magazine - November 2010. To subscribe click here.

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