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           Maya Blue:
An Ancient Mesoamerican Pigment




     Patricia A. Martinez
       December 10, 2006
   Research Paper for 3.983
       Abstract:   The   Maya   blue   [intended   thesis   statement   and

 summary]




 Table of Contents:

I.      Introduction, p. 1

II.     Material Properties, p. 2

III.    Creation: Chemistry, p. 4

IV.     Creation: Process, p. 5

V.      Setting, p.

VI.     Uses, p.

VII.    Conclusions, p.
                                          Patricia A. Martinez



 I.   Introduction

      The Maya are well known for the artistry they've left

in the archaeological record, most notably in polychrome

murals, codices and pottery.   Of all the various pigments,

however, one stands out: the Maya blue.   This turquoise,

blue-green pigment, seemingly resistant to almost anything

time can throw at it, has puzzled and fascinated

archaeologists for nearly a century (Gettens, 1961).

      The reasons why this viscous blue-green paint has

driven archaeologists to study it are many.    Some view it

as a traceable material, potentially instrumental in

tracking and understanding trade and origin of not just the

pigment, but the craft and the artifacts it has been used

on (Chiari, 2003).   Others, as an example of rarely found

stability and durability (Polette, 2002).   It’s clearer and

brighter than most blues at the time, and cleaner than most

paint on the shelves today (Polette, 2002).   It’s been

called the ―most stable pigment ever produced,‖ (Chiari,

2003) and the ―most brilliant and most famous studied

pigment,‖ (Polette, 2002).   Further, its unusual

composition and seemingly simple creation process make it a

                                                          Page 1
                                          Patricia A. Martinez

great example of a new type of material, with unique

properties, which could be applied in present times to

varied uses.



 II. Material Properties

     Maya Blue is different from most other natural

pigments, in that it has both inorganic and organic

components: an indigo, and a clay (Arnold, 2005).

     The indigo is thought to be añíl, a dye made out of a

plant called xiuquilit (José-Yacaman, 1996), or Indigofera

suffrucosi, and native to the Mesoamerican lowlands

(Chiari, 2003).   It has the formula C16H10N2O2 (Fois, 2002).

     The clay is most often palygorskite with other clays

such as sepiolite and montmorillonite in smaller quantities

(José-Yacaman, 1996), but can also be primarily sepiolite

(Hubbard, 2003), depending on the source and materials used

to mix the indigo dye. It is a mixture, with a formula

somewhat like the theoretical formula of palygorskite,

Si8(Mg,Al)4[O20(OH)2{H2O)4]·4H2O (Fois, 2002), and the

theoretical formula of sepiolite, Si6Mg4O15(OH)2·6H2O

(Sánchez del Río, 2006): Si8O20Al2Mg2(OH)2(H2O)44(H2O)

(Sánchez del Río, 2006). This forms a:

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                                         Patricia A. Martinez

  ―group of fibrous clay minerals [with] three
  different types of water molecules in this formula:
  hydroxyl groups, water bonded to octahedral cations
  and absorbed water [which] occupies channels
  parallel to the fibre axis,‖ (Sánchez del Río,
  2006).

The clay shows further complexity, as well, since

palygorskite forms two polymorphs, monoclinic and

orthorhombic, and the ratio between these varies from site

to site (Chiari, 2003).

    These two materials, however, do not show any of the

defining characteristics of Maya blue: neither the

turquoise color nor the impressive stability.

    According to Chianelli,

  "Maya blue is a 'surface compound' with the indigo
  molecule inserted into channels at the clay surface
  and bonded to chemical sites in the channels. [...]
  This channel binding and the resulting charge
  transfer is responsible for the stability of the
  complex and its remarkable color." (2004).


However, neither the stability nor the color is explained

away so simply.   According to José-Yacaman, the color is

caused by encapsulation of the indigo molecules in the clay

substrate as well as nanoparticles — mostly Fe but some Cr,

Ti, and Mn —   embedded in and strongly interacting with the

substrate (1996).   Chiari offers an entirely different


                                                          Page 3
                                        Patricia A. Martinez

hypothesis — that the turquoise color is due to the

formation of hydrogen bonds at the heating stage of the

pigment creation process, and that iron nanoparticles

aren’t present (2003), an interpretation that is

corroborated by Polette (2002).

    The cause of the stability is less controversial: the

basic idea is that the indigo molecules diffuse within the

channels of the palygorskite superlattice, where they

become trapped, safely in a less exposed state than if they

were on the surface of the clay (Fois, 2003).   The compound

is resistant to ―acids, alkalis, moderate heat, solvents,

oxidants, reducing agents, and biocorrosion‖ (José-Yacaman,

1996) simply because it isn’t accessible, deep within the

otherwise colorless clays (van Olphen, 1966).



 III.     Creation: Chemistry

    The creation of Maya blue, according to correlations

between experimental data and data from archaeological

samples, needs to include essential steps: a mixture of

clay and indigo, with two percent indigo by weight

(Hubbard, 2003), a heating process by which the mixture is

heated to 100-150 degrees Celsius, depending on the exact

                                                         Page 4
                                          Patricia A. Martinez

clay composition (Hubbard, 2003; Polette, 2002), and some

means for electrochemical sorption of indigo into the clay

material to occur (Polette, 2002).    Further a detailed

analysis is necessary to verify that the chemical and

physical properties of the prepared sample match those of

samples from archaeological artifacts.    Curiously, attempts

have been made in the lab to synthesize Maya blue with

ingredients and methods that the Maya could not possibly

have used (Sánchez del Río, 2006).

       Van Olphen (1966) attempted to creat Maya blue in the

lab multiple times:    by placing the palygorskite in an

alkaline solution of synthetic indoxylacetate, by heating a

mixture of indigo and palygorskite and then washing it with

acetone, by the ―vat-dyeing technique‖ of using sodium

hydrosulfite to reduce the indigo and then mixing it with

the palygorskite, and by doing all of these with sepiolite

instead of palygorskite (van Olphen, 1966).    Kleber mixed

powdered indigo with powdered clays, and then heated the

mixture (Sánchez del Río, 2006).



 IV.    Creation: Process

The process of making Maya blue pigment can also be

                                                           Page 5
                                          Patricia A. Martinez

approached from an entirely different angle: by analyzing

the ethnographic data gathered by the Spaniards during the

sixteenth century, and piecing together a recipe for the

pigment.

According to Fray Bernardino de Sahagún, for example, the

Maya blue pigment was created by: first boiling the añíl,

torn to leaves and splinters, and then soaking the plant

matter under branches.    Then, after time has passed,

draining it over cotton, ixtle, or tochómitl (rabbit skin)

(Reyes-Valerio, 1993).

       At this point in the colorant-making process, the parts

that didn’t dissolve are pigment and the parts that did are

dye.    Next, tequixquitl was added for dye, and tzacutli for

pigment.    He further noted that mineral-based pigments were

ground, and that mixing occurred to create different tones

(Reyes-Valerio, 1993).

Francisco Hernández, who also kept a record that included

reference to the blue-making process, also failed to

mention clay; however, he noted the precense of large

quantities of sediment in the dye making process – enough

to form roundish lumps with it, as well as the indigenous

peoples’ insistence that the añíl be soaked in river water

                                                         Page 6
                                           Patricia A. Martinez

and not well water (Reyes-Valerio, 1993).     This last

pointing out their knowledge of a need for inpurities in

the final pigment.

       Utilizing these Spanish ethnographic texts, Reyes-

Valerio (1993) attempted to create a comparable pigment,

with only such tools as the ancient Maya would be likely to

have or develop.     His method, not taking account the

palygorskite (but accounting for the necessary heating —

the filtered pigment is tied up and left out in the sun),

produces a deep blue añíl dye (Reyes-Valerio, 1993).

However, this method can be extrapolated to a indigo-

palygorskite scenario, thus producing a Maya blue pigment

in an entirely natural way.



 V.   Setting

      The earliest known use of Mayan blue is at Bonanpak,

Chiapas (Reyes-Valerio, 1993), around 600AD-800AD.

(Hubbard, 2003; Reyes-Valerio, 1993).     The last use of it

is by Juan Garsón in 1562, on panels depicting Christian

imagery in Tecamachalco, Puebla (Reyes-Valerio, 1993).

During the interim it appears, among others, at El Tajín,

Veracruz; Chichén Itzá and Mulchic, Yucatán; El Tamuín, San

                                                          Page 7
                                          Patricia A. Martinez

Luis Potosí; Cacaxtla, Tlaxcala; El Templo Major,

Tenochtitlán; as well as sixteenth century convents in the

present day states of Hidalgo and Puebla, and various sites

in Yucatan and Central America (Reyes-Valerio, 1993).       The

ubiquity with which it is found in the Yucatán peninsula

and the Petén is not surprising, since Maya blue was most

likely discovered in the southeastern portion of the Maya

lowlands (Reyes-Valerio, 1993).

       Of the components, añíl was native to the tropical

lowlands of Mesoamerica (Chiari, 2003), and the

palygorskite was likely from either a cenote in the town of

Sacalum, Yucatan, or a pre-Hispanic mining site at Yo'Sah

Kab, near Ticul, Yucatan. (Arnold, 2005).    Indeed, José-

Yacaman correlates the impurities in some Maya blue samples

with the impurities of the palygorskite at Sacalum (1996).



 VI.    Uses

   Maya blue is used in almost all polychrome Mayan media,

from murals to pottery to codices to figurines.    But this

broad usage was done by only a craftmen, trained from a

young age in the arts of depicting and coloring sacred

images, as well as making the materials — including Maya

                                                         Page 8
                                         Patricia A. Martinez

blue — that were required in the process (Reyes-Valerio,

1993).   In each image, each iconographic detail and each

dab of color had a meaning, and therefore the creation of

art required knowledge acquired over a long period of time,

at Calmécacs, and so the knowledge of the preparation of

the Maya blue pigment was limited to a few handful of

carefully trained elites (Reyes-Valerio, 1993).

   Colors were fundamental to the Mesoamerican people, not

just the Maya, not unlike the way that the same mythology

and religious ideas weave throughout Mesoamerica (Reyes-

Valerio, 1993).   Blue, in particular, was associated with

sacrifice, with the gods of rain and water, and with the

sky, which was often painted as the background to murals

depicting events of great import.   While the color blue was

one of the cardinal directions in highland symbology, it

wasn’t in the Maya lowlands, possibly because the pigment

was not developed until the cardinal symbology was in place

(Reyes-Valerio, 1993).   Indeed, Maya blue is only found in

murals associated with the late classic and postclassic

periods (Reyes-Valerio, 1993).

    On a more practical scale, objects relating to fishing,

medicine, or sacrifice were often painted blue (Reyes-

                                                         Page 9
                                           Patricia A. Martinez

Valerio, 1993).    Further, the paint was mostly applied on

pottery after firing, possibly because it is quite stable

without firing, or because it fades to a dull grey when

heated to temperatures above 250 degrees Celsius (van

Olphen, 1966).



 VII.    Conclusions

    Maya blue is remarkable as a material, as a symbol, and

as a pigment.     It is yet another example, like rubber, of

the Mesoamerican peoples utilizing their resources to

produce materials that suited their needs; an example of a

culture whose gods, like engineers, tried various materials

when creating humanity.    When Europe was griding lapis

lazuli to form an expensive blue pigment, Mesoamerica was

using an ingenious complex material for their blue paint.

All this is remarkable, and not least remarkable is the

fact that the ancient Mesoamerican people developed a

complex material that stumped present-day scientists,

knowledgeable of molecular structure and synthetic

materials, for over seventy years.




                                                        Page 10
                                          Patricia A. Martinez

                         Works Cited:

Arnold, D.
   2005   Maya Blue and palygorskite: A second possible
          pre-colombian source. Ancient Mesoamerica 16:51-62

Chianelli
   2005   Synchrotron and simulations techniques applied to
          problems in materials science: catalysts and Azul
          Maya pigments. Journal of synchrotron radiation.
          12(2):129-134

Chiari G., R. Giustetto, and G. Ricchiardi.
   2003   Crystal structure refinements of palygorskite and
          Maya Blue from molecular modelling and power
          synchrotron diffraction. European Journal of
          Mineralogy 15(1):21-33.

Fois, E., A. Gamba, and A. Tilocca.
   2003   On the unusual stability of Maya blue paint:
                         molecular dynamics simulations.
          Microporous and                    mesoporous
          materials. 57(3):263-272.

Gettens, R.
   1961   Bulletin of the American Group. International
          Institute for Conservation of Historic and Artistic
          Works, 2(1):4-5.

#Giustetto, R., F. Llabrés i Xamena, G. Ricchiardi, S.
Bordiga, A. Damin, R. Gobetto, and M. Chierotti.
   2004   Maya Blue: A Computational and Spectroscopic Study.
          Journal of Physical Chemistry. 106:19360-19368.

Hubbard B., W. Kuang, A. Moser, G. Facey, and C. Detellier
   2003   Structural study of Maya blue: Textual, thermal and
          solid-state multinuclear magnetic resonance
          characterization of thepalygorskite-indigo and
          sepiolite-indigo adducts. Clays and Clay Minerals.
          51(3):318-326.

Jose-Yacaman, M., L. Rendón, J. Arenas, and M. Serra Puche.
   1996   Maya Blue Paint: An Ancient Nanostructured Material.
          Science. 273(5272):223-225
                                                        Page 11
                                          Patricia A. Martinez


Polette, L., G. Meitzner, M. José-Yacaman, and R. Chianelli.
   2002   Maya blue: application of XAS and HRTEM to materials
          science in art and archaeology. Microchemical
          journal. 71(2):167-

#Reinen, D., P. Köhl and C. Müller.
   2004   The Nature of the Colour Centres in 'Maya Blue'--
          the Incorporation of Organic Pigment Molecules into
          the Palygorskite Lattice. Zeitschrift für
          anorganische und allgemeine Chemie. 630(1):97-

Reyes-Valerio, M.
   1993   De Bonampak al templo mayor: El Azul Maya en
          Mesoamérica. México: Siglo XXI Editores.

#Sánchez del Río, M.
   2004   Microanalysis study of archaeological mural samples
          containing Maya blue pigment. Spectrochimica acta.
          Part B, Atomic spectroscopy. 59(10-11):1619-1625.

Sánchez del Río, M., P. Martinetto, C. Reyes-Valerio, E.
Dooryhée, and M. Suárez.
   2006   Synthesis and Acid Resistance of Maya Blue Pigment,
          Archaometry. 48(1):115-130.

#Vandenabeele, P., S. Bodé, A. Alonso, and L. Moens.
   2005   Raman spectroscopic analysis of the Maya wall
          paintings in Ek'Balam, Mexico. Spectrochimica Acta
          Part A: Molecular and Biomolecular Spectroscopy.
          61(10):2349-2356.

Van Olphen
   1966   Maya Blue: A Clay-Organic Pigment?   Science.
          154(3749):645-646.




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