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How an Oyster Makes a Pearl

Rachel Tepper Paley
August 8, 2014

That lovely strand of pearls around your grandmother’s neck? Every single one of those iridescent orbs began its life in the belly of an oyster as a piece of ocean gunk, an errant piece of sand, or food that became wedged inside the oyster’s calcified shell.

So we learn in the above video from SciShow, which breaks down the salty science behind these treasured gems of the sea.

But the rarest pearls of all aren’t the pricey ones gleaming in jewelry store windows. Nope, they’re the ugly little things oh-so-rarely found at the raw bar, tucked between the briny folds of a freshly shucked oyster.

The oysters we eat, whether they hail from the marshlands of Virginia or the glacial waters of Washington State, are called “true oysters.” Although it’s possible for true oysters to produce pearls—it’s a protective reaction to foreign bodies within the shell—they’re without luster and have no commercial value. They’re nothing like the gorgeous things produced by the aptly-named “pearl oysters.”

Pearls are very rarely found in true oysters, but it does happen: In 2013, a British man bit down on a gritty pearl that was inside a freshly shucked Pacific oyster. The previous year, a Mardi Gras reveler in New Orleans discovered one in a fried oyster, and a South Carolinian woman in an oyster-topped pizza.

Cool! But since they’re worthless, we’ll take our oysters pearl-free, thanks very much.