Archaeologists have conducted the largest compositional study ever of obsidian artifacts from the heart of the Mexica Empire, analysing 788 items recovered from the Templo Mayor of Tenochtitlan. The new findings show that obsidian used in both everyday and ceremonial life came from across Mesoamerica, including from lands controlled by rival polities. The results dismantle the long-standing idea that the Mexica obsidian economy was mostly local or restricted to conquered regions. Instead, the data reveals a sophisticated, far-reaching network of exchange that operated from the empire’s rise through to its collapse.
The analysis was conducted by researchers from Tulane University in collaboration with Mexico’s National Institute of Anthropology and History. Using portable X-ray fluorescence technology, they identified eight separate geological sources for the obsidian, including the Sierra de Pachuca, Ucareo, Tulancingo, El Paraíso, Zacualtipán, Otumba, and Paredón. Nearly ninety percent of the entire sample came from Sierra de Pachuca, a source long associated with green obsidian favoured for ritual use. But the remaining pieces came from across the Trans-Mexican Volcanic Belt, indicating access to material well beyond Mexica-controlled territory.
Many of the most distant sources included obsidian typically associated with the Purépecha Empire, the Mexica’s key regional rival. Artifacts made of Ucareo obsidian were found across multiple layers of the Templo Mayor complex, spanning different phases of the Mexica timeline. The researchers concluded that these materials were not only traded during peaceful periods but likely moved through parallel economic routes even during times of tension. The consistency of material from foreign sources implies that diplomatic and merchant relationships existed independently of political rivalry.
The artifacts recovered include blades, flake tools, earrings, pendants, and elaborately carved ceremonial pieces such as scepters and decorated skulls. A clear distinction emerged in the sourcing of materials for different functions. Non-ritual tools and daily-use objects drew on obsidian from a mix of sources. In contrast, ritual items overwhelmingly came from the Pachuca source, especially green obsidian, which carried religious and aesthetic value. The preference was not merely stylistic. Pachuca obsidian held cultural and symbolic meaning tied to Mexica cosmology and priestly authority. The fact that these objects may have been produced in external workshops and brought to Tenochtitlan for ritual use highlights the extent of this value system.
These findings also expose an internal economy structured around controlled access. It was not simply that obsidian arrived in the capital. The flow was deliberate and monitored. Ritual specialists and elite families were granted access to Pachuca obsidian, while lower-status individuals likely purchased their tools from local markets stocked with materials from other deposits. The spatial organisation of obsidian within the Templo Mayor also reveals this divide. Ceremonial caches contained only high-quality green obsidian, while more utilitarian forms were scattered throughout residential or administrative areas.
Researchers believe that the presence of obsidian from these eight distinct locations reflects how the Mexica controlled and accessed resources, not just by force but through persistent trade systems. Even after consolidating power around 1430 CE, obsidian from non-Mexica regions continued to appear. This suggests that merchant routes into the capital remained open and actively maintained. Some deposits, such as Tulancingo and Zacualtipán, appear to have supplied more material in earlier periods, while Otumba and Ucareo became more dominant after imperial centralisation.
Tenochtitlan’s marketplace was among the most active commercial centres in the Americas at the time, documented by Spanish sources to have hosted thousands of daily visitors. These new findings align with that image. They suggest not only large-scale material flows but a diverse economy that absorbed products from multiple competing societies. The choice to use Pachuca obsidian for ceremonial tools, even when other sources were abundant, shows that cultural preferences shaped economic behaviour in ways that transcended convenience or geography.
According to Tulane anthropologist Jason Nesbitt, this project demonstrates how archaeological science can expose the structure of ancient power. By mapping material flows, researchers can now visualise how goods moved through rival territories, circumventing imperial borders. These findings also support written records that describe long-distance traders—pochteca—who were authorised to travel deep into foreign lands under the protection of their empire’s diplomatic agreements.
This survey represents one of the largest datasets ever assembled for obsidian sourcing in ancient Mesoamerica. It is a rare case where chemical analysis intersects with historical archaeology to produce a timeline of material distribution. Each layer of volcanic glass extracted from the temple’s soil represents not just a transaction but a link between people, places, and priorities. Obsidian travelled vast distances across rough terrain to reach the sacred centre of Tenochtitlan, where it was crafted, broken, buried, and eventually rediscovered centuries later.
The logistics of such a trade network were not simple. Obsidian is dense and brittle. Moving it required wrapping techniques, trained carriers, and knowledge of safe transport over rough terrain. It is likely that obsidian entered the city through a centralised system, possibly through merchant guilds or workshops tied to the state. Markets distributed the tools while the elite managed ceremonial imports. This system of exchange also reflects the ideology of the Mexica, who saw the control of resources as evidence of divine favour.
Archaeologists believe the symbolism of obsidian was rooted in its visual and tactile properties. Green obsidian in particular was used to represent fertility, renewal, and sacred fire. The Mexica creation myths often describe the gods as forming the world through sacrifice and fire, and green obsidian was used in rituals to reenact these cosmic acts. Priests used Pachuca obsidian in ceremonial blades, altars, and icons. Even the mirrors used for divination were polished from this material.
At a time when most material economies were hyper-local, the Mexica managed a system that integrated goods from across hundreds of kilometres. This was not just about weapons or tools. It reflected status, belief, and empire-building through matter. Each shard speaks not only to geology, but to power. The Mexica chose their obsidian carefully, reserved the finest for sacred use, and built a distribution system that withstood war, rebellion, and even foreign invasion.
The collapse of the Mexica Empire under Spanish conquest did not erase these patterns. The objects remain. They show where the trade routes went, who had access to what material, and how the elite maintained symbolic control over specific resources. This new study unlocks those patterns with unprecedented clarity. It places obsidian at the centre of imperial logic, where control of materials was indistinguishable from control of people.
Comparing these results with other Mesoamerican sites shows the Mexica system was unique in its intensity. Other cultures used obsidian, but none orchestrated its flow with such ideological precision. For the Mexica, material and meaning were inseparable. Green obsidian was more than a tool—it was a statement. Its presence in ritual caches, inlaid into religious objects, and embedded into skulls confirms its role in representing imperial order.
Through ritual, warfare, and exchange, the Mexica built one of the most interconnected political economies in the ancient Americas. The sharp edges of volcanic glass were not just functional—they were political, spiritual, and symbolic. The research shows that in Mexica civilisation, stone was never just stone. It was a tool of empire.
Source:
Matadamas-Gomora, D., Nesbitt, J., Aguilar Tapia, R., & Pastrana, A. (2025). Compositional analysis of obsidian artifacts from the Templo Mayor of Tenochtitlan, capital of the Mexica (Aztec) Empire. Proceedings of the National Academy of Sciences, 122(20), e2500095122. https://doi.org/10.1073/pnas.2500095122
There’s no doubt that trade routes operated for many centuries up and down the Americas from the American Southwest (and even central North America) to modern-day Honduras.
But this was clearly a VERY detailed investigation of the obsidian trade, important to pre-metallic cultures. Such a study of the trade in jade would also be fascinating.
on May 13, 2025, 6:03 pm
