![]() There are also hurricanes, issues with water quality and pollution, and so on." “It's not a question of if, but how much will saltwater pearls be impacted by ocean acidification,” said Farfan, “And, ocean acidification is only one of the big issues facing all mollusks and pearls. These animals might need to devote more nacre to repair their dissolving shells, meaning less to trap irritants. For example, saltwater mollusks’ shells are weakening from ocean acidification. Species known for creating gem-quality pearls may start redirecting their energy to sustaining other biological needs. “Global warming will shift these ranges, placing the animals under stress, and so we need to study how that stress affects the energy trade-offs that these animals will have to make.” “Mollusks have optimum temperature and environmental ranges, like you and me, where their bodily functions work best,” said Stewart Edie, marine paleobiologist and curator of fossil bivalves at the museum. Global water temperatures are rising, and local habitats are changing, both of which will affect mollusks and could threaten all types of pearl making. Their survival will be challenged in coming years by increasingly inhospitable living conditions. Since pearls come from mollusks’ shell material, like mother of pearl, the fate of pearls depends on the survival of mollusks. “For example, with earrings, it’s about how closely the pearls are matching in size and shape.”Īlthough pearl farming is thriving currently, it faces an uncertain future just like many other aquatic industries threatened by climate change. "It's really the gemologist’s capacity to match them that makes them something really special,” said Meyer. ![]() So, instead of rarity, their value comes from their symmetry and shine. Since the farming process is so effective, cultured pearls are more widely available than their natural counterparts. ![]() Then they gently put the mollusk back into the ocean or a lake and let it grow a pearl over the course of two to five years for harvesting later on,” said Farfan. “Essentially, the pearl farmers very carefully insert a little bead made of shell into the mollusk. (Chip Clark, Smithsonian)įarmed, or cultured, pearls are usually smooth and spherical, because of how they’re made. “There’s this industry that knows how to manipulate pearl production, which has led to all these pearl farms,” said Meyer.įarmed and natural pearls can come in different colors, depending on the color of their parent’s mother of pearl. So, people today farm pearls to make more for the gem market. This brick-and-mortar process dates to at least 200 million years in the fossil record, but natural pearls are incredibly rare. “It’s mineral and organic parts go together like bricks and mortar,” said Farfan. The material’s recipe, made of organic secretions with a carbon-based mineral known as aragonite, makes it exceptionally strong. But it’s also special for another reason. Nacre is a type of rind that gives pearls their pearly sheen. “All the animal is doing is putting a rind around an intruder, like a grain of sand or parasite,” said Meyer. For some animals, this material is nacre, or mother of pearl. ![]() They do so by exuding layer upon layer of shell material. Mollusks make pearls as a protection against irritants that sneak into their soft tissue. Unlike most farmed pearls, natural pearls often stick to their parent’s shell as “blister pearls.” They’re also less smooth but because of their rarity, they’re no less valuable than their cultivated counterparts. “Only certain mollusk groups use a substance, called nacre, which gives gem-quality pearls their opalescent sheen,” said Chris Meyer, a marine invertebrate zoologist and curator of mollusks at the museum.īy collecting and analyzing nacreous pearls, scientists can learn more about how mollusks create these shiny gems and how that biological process could change as Earth’s waters warm. While all mollusks, including oysters, mussels, and clams can technically make pearls, only some saltwater clams and freshwater mussels are used to commercially grow cultured gem-grade pearls. Whitney curator of gems and minerals at the Smithsonian’s National Museum of Natural History. If debris gets stuck in a mollusk and they can’t flush it out, they coat this debris in their own mother of pearl or shell material,” said Gabriela Farfan, environmental mineralogist and Coralyn W. “Pearl is a word we use for a shiny creation that a mollusk produces. But pearls - the most famous biological gems - come from the bowels of mollusks. Most gems come from the bowels of the Earth, made by pressure and heat over millions of years. As with all gems, the less blemishes they have, the more valuable they are. Smooth pearls in the shape of orbs and ovals are usually created by bivalves, like mussels, in pearl farms. ![]()
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