Anthropologists solve mystery of blue pigment used by ancient Mayans

Washington, Feb 27 : Anthropologists have solved the centuries-old mystery of how the ancient Maya produced an unusual blue pigment that was used in offerings, pottery, murals and other contexts across Mesoamerica from about A.D. 300 to 1500.

The anthropologists solved another old mystery, namely the presence of a 14-foot layer of blue precipitate found at the bottom of the Sacred Cenote (a natural well) at Chichen Itz¡.

Chichen Itz¡, one of the seven wonders of the ancient world, is an important pre-Columbian archeological site built by the Maya who lived on what is now the Yucat¡n Peninsula of Mexico.

First identified in 1931, this blue pigment (known as Maya Blue) has puzzled archaeologists, chemists and material scientists for years because of its unusual chemical stability, composition and persistent color in one of the world's harshest climates.

According to 16th Century textual accounts, blue was the color of sacrifice for the ancient Maya. They painted human beings blue before thrusting them backwards on an altar and cutting their beating heart from their bodies.

Human sacrifices were also painted blue before they were thrown into the Sacred Cenote at Chichen Itz¡. In addition, blue was used on murals, pottery, copal incense, rubber, wood and other items thrown into the well.

The new research concludes that the sacrificial blue paint found at this site was not just any pigment. Instead, it was the renowned Maya Blue - an important, vivid and virtually indestructible pigment.

Scientists have long known that the remarkably stable Maya Blue results from a unique chemical bond between indigo and palygorskite, an unusual clay mineral that, unlike most clay minerals, has long interior channels.

Though several studies have found that Maya Blue can be created by heating a mixture of palygorskite with a small amount of indigo, they have not been able to discover how the ancient Maya themselves actually produced the pigment.

Now, the new research has shown that at Chichen Itz¡, the creation of Maya Blue was actually a part of the performance of rituals that took place alongside the Sacred Cenote. pecifically, the indigo and palygorskite were fused together with heat by burning a mixture of copal incense, palygorskite and probably the leaves of the indigo plant. Then, the sacrifices were painted blue and thrown into the Sacred Cenote.

"These sacrifices were aimed at placating the rain god Chaak," said Dean E. Arnold, Professor of Anthropology at Wheaton College, and lead author of the study. "The ritual combination of these three materials, each of which was used for healing, had great symbolic value and ritualistic significance," he added.

ANI