Scientists Revive 'Sea Silk,' the Shimmering Golden Cloth of Emperors Lost for 2,000 Years

For two millennia, "sea silk" was the stuff of legend — a feather-light golden cloth prized by Mediterranean emperors and woven from the fine fibers a clam uses to anchor itself to the seabed. The craft all but vanished, kept alive in the modern era by only a handful of artisans on the Italian island of Sardinia, and the rare clam that produced it slid toward extinction. Now scientists in South Korea say they have brought the fabled material back.

A team led by professors Dong Soo Hwang and Jimin Choi at the Pohang University of Science and Technology recreated the golden fiber using the pen shell Atrina pectinata, a clam already farmed extensively in Korean coastal waters for food. Crucially, they made it from byssus fibers that are normally thrown away as waste, turning a discarded byproduct into a luxury textile. The findings were published June 12 in the journal Advanced Materials.

The original sea silk came from a different Mediterranean species, Pinna nobilis, whose populations have been devastated by marine pollution and disease — so much so that the European Union has banned harvesting it entirely. For centuries, the silky byssus threads that both clams use to lash themselves to the seafloor were gathered by divers and spun into gloves and shawls so fine they could reportedly be folded into a walnut shell. Reproducing the fabric from a sustainably farmed relative offered a way to revive that tradition without threatening an endangered animal.

The researchers also solved the centuries-old mystery of the cloth's enduring shimmer. The golden color, they found, comes not from any pigment or dye but from structural coloration: tiny spherical proteins the team calls "photonin" assemble into nanofibrils that twist together in helical bundles, reflecting light much like a butterfly's wing or a soap bubble. Because the color is built into the fiber's physical structure, it can stay vibrant for centuries rather than fading.

"Structurally colored textiles are inherently resistant to fading," Hwang said. "Our technology enables long-lasting color without the use of dyes or metals." Beyond reviving a piece of ancient history, the work points toward a new class of sustainable, brilliantly colored fabrics produced without the polluting dyes that make textile manufacturing one of the world's dirtier industries — all from the kind of shellfish scraps that usually end up in the trash. Because the pen shell is already cultivated at scale across Korean aquaculture, the researchers say the approach could be expanded without harvesting wild animals, offering both a revival of a lost art and a template for greener manufacturing.