Scholars have undertaken an investigation into the application of obsidian, a naturally occurring volcanic glass vital for tool manufacturing and ceremonial items, and a paramount raw material during pre-Columbian epochs, within the confines of the Mexica (Aztec) Empire. A meticulous examination of 788 obsidian artifacts, encompassing a spectrum of object typologies and contextual placements, was conducted. These artifacts were exhumed from the Templo Mayor of Tenochtitlan (circa 1375-1520 CE), the principal religious edifice and the imperial nucleus situated in present-day Mexico City. The study revealed a distinct preference among the Aztecs for green obsidian originating from the Sierra de Pachuca, yet it also demonstrated a continuous procurement of this valuable resource from seven other distinct geographical origins. These revelations strongly indicate the existence of a highly developed economic system that was underpinned not solely by military conquest but also by robust long-distance commerce, even extending to interactions with rival political entities.
Obsidian artifacts from Tenochtitlan. Image credit: Mirsa Islas / PTM-INAH.
“While the Mexica population favored obsidian of a verdant coloration, the substantial array of obsidian categories identified, particularly within the realm of secular artifacts, implies that obsidian implements originating from various locations were channeled into the Empire’s capital through commercial exchange rather than direct procurement at the source,” posited Diego Matadamas-Gomora, a doctoral candidate affiliated with Tulane University.
“By undertaking the analysis of the provenance of these materials, we gain insights into the patterns of material circulation throughout Mesoamerica.”
The compositional analysis indicated that an overwhelming majority, close to 90%, of the obsidian artifacts subjected to scrutiny were fashioned from obsidian sourced from the Sierra de Pachuca. This particular obsidian was highly esteemed for its characteristic green luminescence and its profound symbolic resonance with the legendary metropolis of Tollan.
The vast majority of the ceremonial objects discovered within the interment layers of offerings at the Templo Mayor were crafted from this specific variety of obsidian. These included miniature weaponry, exquisite jewelry pieces, and intricate inlays intended for larger sculptural works.
A more limited, yet still noteworthy, proportion of the obsidian originated from locations such as Otumba, Tulancingo, Ucareo, and El Paraíso, some of which were situated beyond the direct dominion of the Mexica Empire.
These alternative obsidian materials were predominantly utilized in the fabrication of tools and were frequently encountered within the fill of construction contexts, suggesting that access to these obsidian types was facilitated through local marketplaces for the general citizenry, rather than being subject to stringent state control.
The research also meticulously documented the temporal evolution of obsidian utilization, tracing its trajectory from the nascent stages of the city’s establishment around 1375 CE up to its eventual decline in 1520 CE.
During the earlier periods of the empire’s ascendancy, a more pronounced diversity in the sources of obsidian was discernible in both sacred artifacts and utilitarian items.
Following the consolidation of Aztec authority, approximately around 1430 CE, the sourcing of obsidian for ritualistic purposes became almost exclusively concentrated on materials from Sierra de Pachuca. This shift points towards an increasing trend of religious uniformity and a strengthening of centralized governance.
“This form of compositional examination empowers us to reconstruct the developmental trajectories of imperial expansion, strategic alliances, and commercial networks across historical periods,” stated Matadamas-Gomora.
“This endeavor not only illuminates the far-reaching influence and intricate structure of the Mexica Empire but also underscores the potent capacity of archaeological sciences to investigate ancient artifacts and to decipher the narratives they convey about past societal behaviors,” remarked Dr. Jason Nesbitt, also of Tulane University.
The study’s findings have been published in the esteemed journal, Proceedings of the National Academy of Sciences.
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Diego Matadamas-Gomora et al. 2025. Compositional analysis of obsidian artifacts from the Templo Mayor of Tenochtitlan, capital of the Mexica (Aztec) Empire. PNAS 122 (20): e2500095122; doi: 10.1073/pnas.2500095122
