The Old World
In the Old World, India was the first place to produce blue dye on a large scale. The plant genus indigofera, native to the tropics, was the main source of indigo dye. The very name, “indigo,” refers to India in its Greek roots. India traded this valued commodity widely, doing business as far afield as the Greek and Roman empires. Although temperate regions like Europe have native plants that contain chemically identical indigo, such as woad, the tropical plants yield much more of the extract.
Countries imported indigo at great expense, as it had to be brought over land on long, dangerous routes. The coveted cargo had to find its way through many lands, subject to tariffs, bribes and thievery along the way. Its high value – it was called Blue Gold – and exclusivity led to indigo being used to denote wealth, power and even saintliness. Artistic representations of royalty and religious sanctity commonly used blue to signify them.
The New WorldIn the New World, ancient cultures also had indigofera plants available in their tropical areas. They also made use of color, and they, too, liked their blue. Blue was just as special there as it was in the Old World. Among the ancient Maya it was the color of sacrifice. Humans and other items sacrificed, such as pottery, were painted blue first. It was such a popular practice that a layer of blue almost five meters thick exists at the bottom of the Sacred Cenote, an important sacrificial site.
Maya Blue is unique among the world’s indigo dyes. It is a particularly vivid pigment and, of special interest to archeologists, almost indestructible. The mystery of its durability had eluded them since Maya Blue first came to the attention of science about a hundred years ago. By the 1950s they had determined its composition. Indigo, palygorskite – a type of clay – and copal incense, all used by the Maya for healing, are the ingredients of Maya Blue. But they still didn’t know how it was made.
Dogged persistence eventually paid off. Further research at the Sacred Cenote site revealed that Maya Blue was mixed right there during sacrificial ceremonies, then placed in a fire. When blended in fire, the indigo was infused permanently into the clay, yielding a blue that resists weather, acids, microbial infestations and some modern solvents. Mystery solved.
Whether Maya Blue, Indian indigo or European woad, blue has long been a special color.