Nature’s Take on the Pantone Color of the Year 2018: The Murex Snail

Men with purple fingernails are not a common sight along the remote coasts of Mexico. For a thousand years or so, an elite crew of such men worked their way along the rocky shorelines of Mexico and Central America. These men were the harvesters of one of nature’s most unusual, exotic, and coveted colors: purple. They were the shell dyers, the “milkers” of Purpura pansa, a mollusk cousin to Mediterranean Murex.

When upset, the mollusk excretes a white liquid—the dye. It is dabbed onto a skein carried on the dyer’s arm, and the shellfish is returned to the rocks.

Pre-Columbian Purple

Once upon a time, the Gulf of Nicoya in Nicaragua was the center of a network of trade in purple threads. These cotton threads were woven into the delicious variety of clothing worn in indigenous Mesoamerica before the Spanish conquest of 1521. Yet along a remote stretch of the coast of Oaxaca, a handful of men can still be found with purple fingernails. In the village of Pinotepa de Don Luis, amazingly—astoundingly—sixteen men continue to dye thread with Purpura pansa. It is the last place on the planet where this is true.

Collecting Purpura pansa

During the three-hour window of low tide each day, the dyers scramble over the rocks on sure feet, finding the shellfish in crevices and cracks. With one cautious eye on the pounding surf, each dyer uses a short stick made of mangrove wood to pluck a Purpura off its perch. He gently presses its foot with his thumb, causing Purpura to release its ink. Purpura’s ink is actually a narcotic that it uses to immobilize prey. Each shellfish has perhaps a thimbleful of this milky-white substance. With a skein wrapped around his wrist, the dyer dabs this liquid onto the threads, then carefully places the shellfish, unharmed, back on the rock in a shady crevice where it will adhere and begin to regenerate its ink. One moon cycle later it will be fully recharged, ready to immobilize prey or be milked again by a dyer.

The first Purpura back in place, the dyer continues to work his way along the rocks, plucking shellfish and squeezing their ink onto his skein. After plucking about 300 shells, his skein will be fully moistened and completed. As he works, the ink undergoes a curious process: exposed to air and sunlight, it is transformed from clear to yellow to turquoise and finally to purple, where it stabilizes. The cotton does not need to be mordanted or fixed; the dye simply bonds to the fiber as is. The only additional processing needed is washing the skein to remove the saltwater. The briny smell of the dye itself, however, can never be removed. With time it becomes subtler, yet one can always test a shell-dyed cloth for authenticity by rubbing the threads to warm them up and release the odor. If it smells like a fishy ocean, it is the real thing.

Clockwise from top left: The Purpura mollusk yields its dye while remaining unharmed. While the skein is only partially dyed, the purple section has reached its final color. The dyer will return during low tide to continue dyeing this skein. Exposure to air and sunlight develop and fix Purpura. It transitions from yellow to turquoise to purple in less than an hour of exposure.

Purpura Persists

The remoteness of the Mixtec villages on the coast of Oaxaca has protected them from modern influences until very recently. The fact that purpura is unharmed during the harvest of its ink has allowed this shellfish to also survive. This unique combination of circumstances has led to this far corner of Mexico being the last place on earth where shell dyeing as a tradition persists. Tremendous challenges face the last sixteen dyers and the artisans who still weave this purple thread, but for the moment, the men with purple fingernails are still hard at work.

—Eric Mindling

This is an excerpt of the article “Purple Nails, Purple Thread, which originally appeared in Colorways 2012 (no longer available). You can learn more about natural dyes in our free eBook Guide to Dyeing Yarn. For more fiber treasures of the sea, learn about sea silk in “New Twists on Old Fibers” by Christina Pappas, Spin Off Fall 2017.