Maya blue–green pigments found in Calakmul, Mexico: a study by Raman and UV‐visible spectroscopy

Abstract

After more than two decades of fieldwork in the Maya archaeological site of Calakmul, Mexico, numerous remnants of blue and green pigments have been reported on wall paintings, as well as on funerary paraphernalia, such as masks, miniatures and vases. The importance of these pigments is linked to the sacred values that Maya people associate with blue and green colours since preColumbian times. These hues symbolise water, and are therefore associated with fertility and regeneration. This paper aims to perform a survey of the blue and green pigments used in the Early Classic and Late Classic periods in Calakmul (300-850 A.D.), in order to have a better understanding of their chemical composition and origin. Analyses were performed on microsamples using Raman and UV-visible spectroscopies to evaluate the possibilities that these techniques can offer in future in situ researches on Mesoamerican archaeological materials and objects. With these analyses, we have documented a large blue-green chromatic palette, which includes the earliest Blue Maya and Green Maya known to date, as well as malachite, pseudomalachite and an unknown-up-tonow blue-green mineral pigment, veszelyite, used specifically for ritual objects. The results indicate a careful selection of imported products and the mastering of a complex ancient Maya pictorial tradition.

Application of solid-state electrochemistry techniques to polyfunctional organic–inorganic hybrid materials: The Maya Blue problem

“…4 shows the normalized diffuse reflectance spectra for 1% indigo + palygorskite specimen treated at 180°C for times t = 0, 10 and 60 min. Such spectra are close to those repeatedly described in literature [8,27,29,34,35,55,56] and present spectral features attributable to indigo plus dehydroindigo. It should be noted, however, that, in view of the crushing preparation procedure used for the preparation of the material, a certain amount of indigo remains as solid indigo grains rather than as palygorskite-associated units.…”

“…In fact, the spectra of heated specimens show bands centered at 675, 525 and 440 nm. The first absorption maximum corresponds to palygorskite-associated indigo [55] whereas the last two wavelengths are coincident with the absorption maxima reported for dehydroindigo in solution (440 nm [55,56]) and in solid state (525 nm) [55]. Remarkably, the difference spectrum between spectral curves for t = 0 and t = 10 min, also shown in Fig.…”

Raman spectroscopy of minerals and mineral pigments in archaeometry

“…Wiedemann et al claimed that original Maya blue was used to illuminate a fragment of the ‘Codex Huamantla’, but the conclusion was questioned by del Rio and Montes . Moreno et al studied Maya blue–green pigments found in Calakmul, Mexico, whereas Manciu et al considered the chemical bonding occurring between thioindigo and inorganic palygorskite, synthesizing a pigment similar to Maya blue. A review of the Raman results on Maya blue is given by Doménech et al They also considered the Maya blue samples and models obtained by the binding of indigo to phyllosilicate clays, such as palygorskite and sepiolite, using chemometric analysis.…”

“…Garcia Moreno et al investigated the blue–green chromatic palette in early Classic and Late Classic periods in Calakmul (300–850 ad), including Maya blue and Maya green. In addition to copper‐based pigments like malachite or pseudomalatiche, they identified veszelyite as a green pigment in blue–green mosaic, polychrome masks and funerary offerings from the royal tombs.…”

On the interpretation of the Raman spectra of Maya Blue: a review on the literature data

“…[33,34] The recent reports of MB samples dated in the Late Preclassic [33,34] and in the Early Classic [35] periods extend by several centuries the period of use of this pigment in the pre-Columbian world. The oldest MB sample currently studied was found in the polychrome I of the II C Substructure in the archaeological site of Calakmul, dated in the Late Preclassic period.…”