Some nameless man, lost to us in the annals of time and history, had the brilliant notion that at the heart of every pearl was a grain of sand that had somehow found its way inside an oyster. This undeveloped notion certainly had enough romanticism and magic to appeal to our boundless imagination, and the fable stuck. You would be hard-pressed to find someone who has not heard of the legendary transformation from grain of sand to gem of queens. But what is the true story of how a pearl comes to be?
Why the Grain of Sand Theory Doesn’t Hold Water
It is true that an oyster, or mollusk to be more general, progressively coats an irritant in layer after layer of richly lustrous nacre, so our wayfaring dreamer was not too far off in the origins of pearls. But a grain of sand? Think for a moment how many grains of sand there are in the world’s oceans and in particular, the habitats favored of bivalves – shoreline shallows where movement and wave continually stir up sand. Add to that the fact that mollusks are filter feeders, which continuously open and close their shells to draw in the nutrients that happen to float by.
If a pearl were formed each time a grain of sand entered a mollusk, pearls would not be the rare and prized gems they are today. Mollusks have become well adapted to cleansing their soft tissues of pesky sand by secreting a viscous fluid that collects any rogue particulates. This is then elegantly evacuated from the shell. But sometimes, just every so often, a truly aggressive irritant like a worm or parasite manages to bore through the shell and wedge itself deep within the organs and soft tissues of a mollusk.
How Pearls Are Really Formed
When this happens, there is a good chance that the intruder either lodges in the mantle tissue (next to the epithelial cells that stimulate mother-of-pearl production) or it drags a few of these cells along as it penetrates deeper into the mollusk. Because epithelial cells do what epithelial cells do, they continue to produce nacre – only this time the cells are no longer lining the shell; they are surrounding a particulate. As long as the cells are viable, which can be for many years, they excrete nacre throughout their newfound home. As this nacre-wrapped irritant turns and turns, it becomes in time the charming pearl.
So the next time you hear an offhand remark about a grain of sand, you can hold your chin high in confidence knowing that epithelial cells wrapped about an irritant, and not a grain of sand, is the real reason that our beloved Spey pearls exist. The only thing left is to fashion the pearls into the fabulous jewelry of the Spey collection.