New research uncovers how shimmering green obsidian connected the heart of the Aztec Empire to distant lands — and exposed a sophisticated economy built on more than conquest.
Key Points at a Glance
- Tulane-led study analyzed 788 obsidian artifacts from the Templo Mayor in Mexico City.
- Most ceremonial items were crafted from prized green obsidian from Sierra de Pachuca.
- Materials from at least seven other sources show evidence of wide-reaching trade.
- The Mexica relied on both conquest and active commerce, even with rival regions.
- Obsidian use became more standardized as imperial power and religious control grew.
A new study from Tulane University has revealed a glittering roadmap of the Aztec world — one etched not in stone carvings, but in the chemical makeup of volcanic glass. Obsidian, prized by the Mexica civilization for its sharpness, beauty, and spiritual significance, is now telling a powerful story of trade, religion, and imperial control in ancient Mesoamerica.
The findings, published in Proceedings of the National Academy of Sciences, center on 788 obsidian artifacts excavated from the Templo Mayor in the former Aztec capital of Tenochtitlan, present-day Mexico City. Led by Tulane researcher Diego Matadamas-Gomora, the study represents the most extensive compositional analysis of obsidian ever conducted at the site — and the results offer a nuanced view of how this volcanic material moved through the vast web of Aztec society.
Using portable X-ray fluorescence (pXRF) technology, the team was able to geochemically match each artifact to its origin. Nearly 90% of the obsidian analyzed came from Sierra de Pachuca, known for its emerald hue and mythological resonance with the city of Tollan, a revered place in Aztec cosmology. These materials were overwhelmingly used for ceremonial purposes — miniature weapons, inlaid sculpture pieces, and jewelry buried within temple offerings.
But it’s the remaining 10% that speak volumes. The researchers found obsidian sourced from at least seven other locations — including Otumba, Tulancingo, Ucareo, and El Paraíso — some of which lay outside the Mexica Empire’s political domain. These fragments were more commonly used for practical tools and found in construction fill, suggesting they were acquired not by imperial mandate, but through open market trade. Remarkably, some of this obsidian came from rival territories like the Purépecha in West Mexico, demonstrating the Mexica’s willingness to engage economically even with adversaries.
“Although the Mexicas preferred green obsidian, the high diversity of obsidian types, mainly in the form of non-ritual artifacts, suggests that obsidian tools from multiple sources reached the capital of the Empire through market instead of direct acquisition,” says Matadamas-Gomora.
The researchers also observed how obsidian use evolved over time. In the early stages of Tenochtitlan, beginning around 1375 CE, there was greater diversity in obsidian sources across all artifact types. But by 1430 CE, after the consolidation of Mexica power, a shift occurred: nearly all ritual obsidian came exclusively from Sierra de Pachuca, signaling tighter religious control and increased centralization of sacred practices.
This duality — an empire built on both conquest and commerce — reshapes our understanding of the Mexica economy. It wasn’t just a military machine; it was a finely tuned network of strategic alliances, trade routes, and cultural exchanges.
“This kind of compositional analysis allows us to trace how imperial expansion, political alliances and trade networks evolved over time,” Matadamas-Gomora explains.
The study is a collaboration between Tulane University and the Proyecto Templo Mayor of Mexico’s National Institute of Anthropology and History (INAH). Co-authors include Jason Nesbitt, Julia Sjödahl, Tatsuya Murakami, and INAH experts Leonardo López Luján, Rodolfo Aguilar Tapia, and Alejandro Pastrana.
“This work not only highlights the Mexica Empire’s reach and complexity,” says Nesbitt, “but also demonstrates how the archaeological sciences can be leveraged to study ancient objects and what they can tell us about past cultural practices.”
More than just tools or ornaments, these obsidian shards serve as tiny time capsules — revealing how a mighty civilization balanced faith and function, dominance and diplomacy, all through the razor-thin edge of volcanic glass.
Source: Tulane University
