“How can this blue color remain so vibrant after more than 1,000 years in the harsh conditions of the Mexican jungle without fading?” wondered mineralogist Herbert E. Merwin in 1931. He had just discovered Maya Blue in the ancient murals at the Temple of the Warriors in Chichén Itzá on Mexico's Yucatán Peninsula.
The vibrant color ranges from a bright turquoise to greenish hues of blue and it withstands even acids, high temperatures, and alkalis. After Merwin’s finding, the search for Maya Blue surged and in 1946 American photographer Giles Healey together with local Lacandon Maya of Chiapas discovered even more strikingly well preserved paintings at the ancient Mayan city Bonampak.
For decades, scientists around the world have struggled to unravel the mystery behind Maya Blue’s composition and production, until Mayan ceramist Luis May Ku found a way to recreate its ancient formula.
Ancient Nanotechnology: What is Maya Blue Made Of?
Countless studies have been made to learn about the ingredients of Maya Blue. First, the researchers assumed the pigment consisted of inorganic matter originating from rocks. However, soon the tests revealed that Maya Blue is a hybrid, made of organic and inorganic components.
To understand its longevity, we need to look at the science behind it. The main ingredients are indigo, a vegetable dye, palygorskite, a rare clay mineral with long interior channels, and copal, a natural resin.
When the ingredients are mixed and heated, the indigo molecules enter the Palygorskite channels where they get trapped. The Copal acts like a key locking the color which explains Maya Blues durability. Scientists refer to this manipulation of materials at the molecular and nanoscale as a nanocomposite, an example of ancient nanotechnology.
What Is the Cultural Significance of Maya Blue?
In addition to the proof that the Mayan people had advanced scientific knowledge, Maya Blue also had a special meaning for the Mesoamerican civilization–it was considered a sacred color often used in ceremonies.
The blue pigment decorated offerings such as pottery, clothing, sculptures and even the bodies of human sacrifices before the priests drowned them in a sacred underwater cave, also known as a cenote, to please their rain god Chaac, who lived in the underwater world. He was summoned to prevent droughts and ensure a lush harvest.
Although Herbert E. Merwin contributed to the international interest surrounding Maya Blue, he wasn’t the first to discover the color. Years earlier, at the beginning of the 20th century, archaeologist Edward Herbert Thompson drained the sacred well and discovered a blue layer of the Mayan pigment that had washed off the bodies, ceramics and other objects found at the bottom of the cenote. However, during that time, his discovery didn’t spark much curiosity within the scientific community.
How Was Maya Blue Made?
Even after solving the mystery of its composition, the production process of Maya Blue has puzzled scientists for decades. How were the Mayans able to mix the ingredients to achieve the durability of the pigment? Researchers experimented with Indigofera leaves and a combination of water and clay or mixed and heated palygorskite with indigo, but no outcome was satisfying.
Despite decades of research, no modern experiment could fully replicate the pigment’s unique durability—until an indigenous ceramics artist, Luis May Ku, took a different approach. Instead of relying solely on scientific analysis, he turned to the wisdom of his own Mayan heritage. He spent years investigating, reading scientific papers and ancient texts, experimenting with different recipes.
He realized that to effectively gather information he needed to find out what the Mayan word for Indigo was. This would allow him to interview the elders about the plant’s traditional knowledge, passed down through generations. Ch’oj, as the local plant is called in Mayan, was no longer used to create the blue pigment, but instead served as a natural remedy to treat stomach pain.
However, through his investigations within the community May Ku still learned about another use of Ch’oj, which was used to whiten clothes. The elders revealed a crucial clue: When left too long in the water, the clothes would turn blue. That showed the local indigo plant contained a blue pigment, the missing ingredient May Ku was searching for.
The Blue Formula Decoded and Verified
With the help of the Mayan community, he planted the indigo near the cultural centre where he worked as a teacher. It took many failed attempts until he finally found the ancient formula. As al Jazeera reports, he experimented with various natural additives, tried freezing ch’oj, letting it decay. He combined ink extracted from variants of Indigofera suffruticosa with either sepiolite or palygorskite clays in various combinations until he finally recreated Maya Blue.
May creates Maya blue by soaking ch’oj leaves in alkaline water (lime or ash) for 24 hours in a concrete vat. After straining, palygorskite clay from nearby caves is placed at the bottom to absorb the tint. The blue clay is then baked at 250°C (480°F), ground into a fine powder, and stored in a small flask for sale.
To be sure of its authenticity, May Ku sent samples to two researchers–one to David Buti from the Institute of Heritage Science of the National Research Council in Perugia, Italy and the other one to Rodolfo Palomino Merino, a professor of physics and mathematics at the Autonomous University of Puebla in Mexico. Merino confirmed with a 95 % probability that the rediscovered production process was viable. Buti’s analysis showed a 100 % match. After 200 years he was the first to recreate Maya Blue in its traditional way.
The Colonial History of Maya Blue
During the colonisation period, Maya blue, along with other resources of the New World, was exploited by the Spanish. As an in-depth article of Mazya Blue’s history by BBC mentions, the Spanish controlled the prized colourant until synthetic substitutes started to appear in the late 17th to early 18th centuries. Knowledge of Maya blue then disappeared until its rediscovery in the 20th century. The colours, which supposedly represented the wealth of the Maya empire, would stand as a symbol of all that would be plundered. Even in the 17th century, Mexican artists in New Spain were using Maya blue in their works, a luxury that European painters of the time could not afford.
The colonial history is also the reason May Ku decided not to patent his Maya Blue recipe. Instead, he decided to share it only with his family to protect it from corporations capitalizing on it and let history not repeat itself.
