Non-Invasive Characterization of Stone Artifacts from the Great Temple of Tenochtitlan, Mexico

The Museum of the Great Temple of Tenochtitlan in Mexico City holds a collection of several thousands of polished stone artifacts that were excavated and identified as temple offerings. These can stratigraphically be related to the sequential construction stages (II-VII) of the ceremonial area of the Aztec capital from the foundation of the city in 1325 to 1521, when the Spaniards conquered the city. A non-destructive investigation of the elemental and chemical composition of these archaeological artifacts helps us to understand the provenance of these pieces, their use and the specific mineralogical choice for these artifacts as well as more information regarding trade routes relevant to the development of the Aztec empire. A mineralogical analysis of, in total, 450 stone artifacts was carried out using infrared spectroscopy (FTIR) and X-ray Fluorescence (XRF). From this, eighty-five pieces were selected according to their excavation location, either in the Great Temple itself or in the surrounding buildings, as well as to represent the different construction stages of the area (this is part of a World Heritage Site). The resulting mineralogical and chemical information was related to possible mineral resources that were controlled and used as the empire expanded. Artifacts made from high-status semi-precious minerals, like jadeite and turquoise, are found to be concentrated in the central buildings and in the Great Temple itself, but also in the later construction periods of the area.