These days you can make clothes out of everything. People are wearing gold shirts, duct tape prom dresses, and even red carpet outfits made of meat. But back in the day (way, way back), the most valuable fabric on the market was made of mollusc beards.
The fact that mussels even have beards was fairly novel to me. If you’re imagining a cheerful little clam with some very hipster facial hair, we’re in the same boat (weak pun intended). Apparently, bivalve molluscs like clams have a bit of a hard time attaching themselves to solid objects, so they secrete sticky threads made of keratin and other proteins out of their feet in order to adhere themselves to rock crevices; these filaments are known as byssus.
In the Mediterranean, the mollusc species Pinna nobilis (also known as a pen shell) has been harvested for its byssus for thousands of years. Although the pen shell can grow up to a meter long, its byssus filaments are rarely over 6cm long each, and must be woven together to create threads finer than silk. When treated with lemon juice, these fine threads acquire a permanent golden color and can be woven into highly prized cloths which are both extremely lightweight and extremely warm.
Byssus was highly prized in the ancient world. In some scholarly interpretations, the Golden Fleece sought by the mythical Greek hero Jason was woven byssus cloth. The Veil of Manopello — the fabric believed to have been used by Saint Veronica to wipe the face of Jesus as he carried the cross and then miraculously imprinted with the image of Jesus’ face, now kept as a sacred relic in Rome — is also almost certainly woven of byssus.
Also known as “sea silk”, byssus was one of the most valuable commodities in ancient markets, even more so than other better-known treasured textiles like silk or purple dyed cloth. Byzantine records list byssus robes as being reserved exclusively for the ruling class, sometimes given as gifts by the emperor to his governors. In Persian and Arab chronicles, a robe made of sea silk would cost over 1000 gold pieces, and its origins were treated as almost mystical.
Today, due in great part to the Industrial Revolution and the rising popularity of less expensive, mass-produced synthetic textiles, byssus weaving is nearly a lost art. Most existing sea silk is found in museums, and wearing it is nearly unheard of. Perhaps being clothed in the luxurious, lemon-soaked foot secretions of clams has just fallen out of fashion.