Washington, April 21 : In a new research, scientists have determined that the ancient Maya civilization used a rare type of clay called "palygorskite" to produce Maya blue, a unique bright blue to greenish-blue pigment.

As part of the research, the Spanish research team defined the features of palygorskite clay on the Yucatan Peninsula in Mexico.

These findings will make it possible to ascertain the origin of the materials used to produce this pigment, which survives both time and chemical and environmental elements.

The team traced the route followed by the Maya to obtain palygorskite clay, one of the basic ingredients of Maya Blue.

"Our main objective was to determine whether the Maya obtained this clay from one place in particular," said co-author of the study Manuel Sanchez del Rio, a physicist at the European Synchrotron Radiation Facility in Grenoble (France).

Palygorskite clay has been used in Mesoamerica since ancient times.

Numerous data suggest the Maya were aware of its properties and, what is more, this clay was closely related to socio-cultural aspects of the Mayan culture.

"Present day native communities on the Yucatan Peninsula are familiar with and use palygorskite clay for a variety of purposes, ranging from making candles on All Saints' Day and household and artistic pottery to remedies for mumps, stomach and pregnancy pains and dysentery," said Sanchez del Rio.

However, palygorskite was mostly used to make the Maya blue pigment, which is produced by mixing indigo, an organic dye obtained from the plant of the same name, with a base of palygorskite clay.

The resulting compound is extraordinarily resistant to chemical and environmental elements.

The researchers found samples of high-purity palygorskite clay in several locations on the Yucatan Peninsula, in a 40 km radius of the well-known Maya archaeological site of Uxmal.

Some of these locations are well documented, but others have been discovered for the first time during this expedition.

The fact that this clay was abundant among the samples collected confirms that the mineral is common on the peninsula.

Crystal-chemical analysis then enabled researchers to obtain the formula for the composition of Mayan palygorskite clay: (Si7.96Al0.07)O20 (Al1.59Fe3+0.20Mg2.25) (OH)2 (OH2)4Ca0.02Na0.02K0.04 4(H20).

These results will be useful for studying archaeological remains with Maya blue and to determine whether the palygorskite clay used in the pigment was taken from Uxmal or the surrounding area. (ANI)