The occurrence of a titanium dioxide/silica white pigment on wooden Andean qeros: a cultural and chronological marker

Abstract

A white pigment found on a sub-set of polychromed wooden Andean ritual drinking cups called qeros has been characterized by X-ray diffraction, X-ray fluorescence spectroscopy and Raman spectroscopy as consisting principally of cristobalite (SiO 2 ), anatase (TiO 2 ), and α-quartz (SiO 2 ). This unexpected assemblage of minerals is like that reportedly found in an exposed titanium ore body in southern Peru, an area once part of the Inka Empire. The ore is a close match in color and composition to the white pigment found on the qeros and offers a possible candidate for the geological source of this material. The temporal horizon for the use of this pigment appears to be ca. 1532-1570, correlating with what we refer to here as the Transitional Inka/Early Colonial period, although production of polychromed qeros may have begun before this time and certainly continued well into the eighteenth century or later. Not long after the arrival of the Spanish, this titanium dioxide/silica pigment was replaced by lead white, a result of Spanish influence. We suggest that white pigments on qeros offer material evidence for establishing a chronology for these ritual vessels and that the titanium dioxide/silica pigment on this group of qeros constitutes a previously unidentified, naturally occurring white pigment indigenous to the southern Andes, the first use of which probably dates to the PreColumbian period.

In search of Humboldt’s colors: materials and techniques of a 17th-century lacquered gourd from Colombia

“…While SERS of a microscopic sample removed from the object's inner neck (S2) failed, likely due to the interference of the thick mopa mopa layer in which the dye is embedded, extraction with BF 3 and methanol followed by HPLC-PDA analysis enabled the conclusive identification of carminic acidthe main coloring component of cochineal-and some of its methylated derivatives (Additional file 2: Figure S2). This dye, also found by other researchers in a selection of Andean qeros [30,31], was particularly popular in the 16th and 17th centuries, becoming the third most profitable traded commodity from the New World for the Spanish after silver and gold, and displacing kermes as the source of luxurious crimson and scarlet textiles within 50 years of its introduction [65]. Called grana by the Spanish, it had been cultivated on Opuntia cacti from about 600 C.E.…”

“…Whites commonly used in South American artifacts have ranged from calcium-containing minerals, such as calcite, gypsum, and apatite [61][62][63][64], to lead white [65]. Similarly, scientific analysis carried out to date on qero cups has highlighted a predominant use of lead white in the form of hydrocerussite (basic lead carbonate, 2PbCO 3 •Pb(OH) 2 ) and cerussite (neutral lead carbonate, PbCO 3 ) [5,6], along with a naturally-occurring mixture of cristobalite (SiO 2 ), anatase (TiO 2 ), and α-quartz (SiO 2 ) [30,66]. In the collection of the HSML, lead white was detected in a barniz de Pasto box dating to 1684 (Newman R, Unpublished report, 2015), and this finding appeared to support Humboldt's description of white in barniz de Pasto objects as "made imperfectly with white lead oxide" [14].…”

“…Visual examination followed by analysis with polarized light microscopy, electron microprobe spectroscopy, FTIR, and gas chromatography/mass spectrometry (GC/MS) provided insight on wood identification and found the qeros' decoration to be mostly composed of mopa mopa resin with orpiment, cinnabar, a few unidentified organic reds, lead white, indigo, and copper-based greens. A subsequent publication by a team including the same authors [30] explores the occurrence of a titanium dioxide/silica white pigment on 12 wooden Andean qeros, characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), and Raman spectroscopy as mainly consisting of cristobalite, anatase, and α-quartz. Another article by Newman and Derrick [31] focuses on the identification of mineral pigments, synthetic inorganic compounds, and natural dyestuffs in a number of paint samples removed from qero cups in the holdings of four museums across the United States.…”

Tradiciones técnicas y producción cerámica virú-gallinazo y mochica: nuevas miradas sobre las relaciones entre dos grupos sociales del Período Intermedio Temprano en la Costa Norte del Perú

“…Las principales fuentes de anatasa conocidas las encontramos a mayores distancias hacia el sur, en el Depósito Santa Fe en la provincia de Islay (Arequipa) (mindat.org) y notablemente en el depósito Giacomo en la provincia de Tacna (Tacna), a 600 y 800 kilómetros, respectivamente, en línea recta desde Puerto Nuevo. Este último parece ser la fuente de anatasa utilizada en los pigmentos blancos que decoran keros de madera Inca del Horizonte Tardío (Howe et al 2018). Sin embargo, tal y como nota Enrique Guadalupe, uno de los autores de este artículo, el Ti es común en las arenas de playas antiguas de Arequipa y Tacna, en la forma de óxidos de titanio.…”

The Song Dynasty Shipwreck Monitoring and Analysis Using Acoustic Emission Technique

“…Park et al [7] successfully identified the types of trees and surface materials of a lacquered wooden coffin by using Pyrolysis/gas chromatography/mass spectrometry. In the same year, Howe et al [8] helped archaeologists analyze the pigments of a sub-set of polychromed wooden Andean ritual drinking cups called qeros and its chronological marker by means of X-ray diffraction, X-ray fluorescence spectroscopy, and Raman spectroscopy.…”