Conch Pearl Buying Guide
What are Conch Pearls?
Conch (pronounced “konk”) pearls aren’t true pearls. Produced by the gastropod Strombus gigas, or Queen Conch, conch pearls have no nacre. Instead, they contain the mineral aragonite, the principal constituent of nacre, in a different configuration. While some still consider these to be “pearls,” we at IGS prefer to use the term “calcareous concretions” to describe these gems. However, we also acknowledge the persistent and popular use of the name “conch pearl.”
Commonly called “the pink pearl,” these gems are exceedingly rare. About one in 10,000 conchs creates a pearl, and only 10% of these are gem-quality. These organic gems are perfect for those seeking something rare from nature, though they do come with a hefty price tag.
Conch Pearl Buying Quality Factors
The four Cs of colored gemstone grading aren’t the best way to evaluate either nacreous or non-nacreous pearl quality. Instead, the calcareous concretion’s color, flame structure, luster, shape/symmetry, texture, and size determine quality.
The IGS conch pearl value listing has price guidelines for conch pearls of all sizes.
Conch pearls occur in the same colors as conch shells: orange, yellow, brown, white, and, most famously, pink. Brown, the most common color, generally has a low value. Orange and yellow hues are more desirable than brown. However, they only command up to half the prices of equivalent pink and white gems.
Pink conch pearls can have slight orange or purple secondary hues. While orange is more common and quite attractive, a purer pink hue will be more expensive. However, purple secondary hues are highly prized for their rarity and beauty.
Rare and highly coveted, white can also fetch a good price. Snowy white conch pearls are slightly less expensive than traditional pinks.
Color should be even, without mottling or spots.
The most important factor in distinguishing top-quality conch pearls is the presence of a visible “flame structure.” This effect is sometimes described as being similar to chatoyancy or the “cat’s eye” effect. However, instead of a single bright line, the effect dances in waving patterns across the gem.
While all conch pearls exhibit this effect, you can see it without magnification only in top-quality specimens. A clearly visible flame structure will double the price of a conch pearl. Gems with exceptional flame will sell at a premium. This “flame structure” arises from the criss-cross pattern of aragonite layers in the conch pearl, similar to overtone and orient in nacreous pearls.
A conch pearl’s luster should be sub-vitreous and comparable to silk or porcelain. Dull gems don’t hold as much value as those with a slight sheen.
Conch pearls may dull with exposure to sunlight. However, a careful polish can restore their luster. Consult with an expert if you think your conch pearl has lost its luster in the sun.
Shape and Symmetry
Unlike the cultured nacreous pearl, very, very few conch pearls are round or even close to round. The standard for conch pearl shape is a symmetric oval. As shapes steer away from a symmetric oval, they hold less value. Eggs and teardrops rank as the second and third most valued shapes, respectively. Asymmetry will lower the value of a conch pearl.
As with nacreous pearls, the surface of a conch pearl should be smooth and free of blemishes. Thus, bumps, dimples, and other imperfections will lower the value of the gem.
While most conch pearls are under 3 mm in size and 0.2-0.3 cts in weight, much larger gems do occur. However, anything over 10 cts is exceptionally rare. Prices jump at 1, 2, and 3 carats.
Strombus gigas is a major food source for inhabitants of the islands where it lives. However, due to overfishing and degradation of water quality, the Queen Conch is an endangered species. Because of this, harvesting conch without a proper fishing license is illegal, as is any collection of conch from Florida and surrounding Federal waters.
To avoid illegally and unsustainably collected conch pearls, always purchase from a trusted source.
Jewelry Considerations and Care
Conch pearls, though harder than nacreous pearls, are still somewhat soft and may be scratched. Use in pendants, earrings, and brooches can minimize the risk of such damage. Furthermore, when purchasing conch pearl jewelry, pay attention to the setting. Some connoisseurs believe that drilling a conch pearl lowers its value. Glued settings should also be avoided, as the chemicals in glue can damage these fragile gems.
Exposure to sunlight can cause color to fade as well as dull luster. While dulled conch pearls may be carefully polished, this process will reduce their value among connoisseurs. On the other hand, color fading is unfortunately irreversible. Restrict conch pearl jewelry wear to evenings and store these pieces in a dark, enclosed box to keep them bright and lustrous.
Never use chemical or mechanical cleaners on conch pearls. Instead, wipe them with a non-abrasive cloth before storage and use only water and mild soap for cleaning. The IGS care guide for opals and pearls has more recommendations for handling these delicate gems.
Cultured Conch Pearls
While conch pearls have yet to be commercially cultured, culturing processes are in intense development. Dr. Hector Acosta-Salmon and Dr. Megan Davis of the Harbor Branch Oceanographic Institute at Florida Atlantic University developed methods of culturing conch pearls. In 2010, they formed Rose Pearl, LLC to refine the process. Soon, their success may bring cultured conch pearls to mainstream consumers.
Conch Pearl Simulants
The most convincing simulant or imitation for a conch pearl is conch shell. Indeed, visitors on a conch pearl buying trip to Caribbean islands sometimes find that their souvenir is simply a beautifully carved piece of shell. Buyer beware.
Still, if you’re seeking a conch pearl aesthetic without the price tag, conch shell is the perfect choice. Pink opal can also resemble conch pearl. However, it doesn’t exhibit a flame structure.