MEXICO CITY.- Imagine pulling a forgotten diary from a dusty attic, and suddenly, entire chapters of your family's history come to life. That's precisely what archaeologists are doing at Mexico City's sacred Templo Mayor, but instead of old journals, they're "reading" tiny chips of volcanic glass, and the story they're telling is utterly fascinating.

A new, groundbreaking study has just revealed that the mighty Mexica empire – the civilization at the heart of what we now call Mexico – was far more sophisticated in its trade than we ever fully understood. Forget simple supply chains; their world was a bustling, complex marketplace, even exchanging goods with rivals, defying previous assumptions about their centralized power.

Leading this incredible detective work is archaeologist Diego Matadamas Gomora. His team, a collaboration between Mexico's National Institute of Anthropology and History (INAH) and Tulane University in the U.S., analyzed a staggering 788 obsidian artifacts found within the sacred Templo Mayor. These pieces, dating back to the Mexica's heyday between 1375 and 1520, tell a rich tale of commerce.

While the famous green obsidian from the Sierra de Pachuca quarry was indeed their top pick, the study's high-tech X-ray analysis pinpointed origins from at least seven other Mesoamerican locations. Think of it: a piece of sacred mirror or a sharp knife used in a Tenochtitlan ritual could have traveled hundreds of miles, crossing territories that weren't always friendly.

"Obsidian diversity increased as Tenochtitlan's power solidified," explains Matadamas Gomora. "In the early phases, it was mostly just Pachuca and Otumba obsidian. But after they defeated Azcapotzalco and formed the Triple Alliance, there was an abrupt shift – going from two or three sources to up to seven." This suggests a thriving market system that grew along with the empire.

This discovery is a major win for archaeologists, as it refines long-held theories. Many experts debated whether the Mexica state strictly controlled all trade, or if goods moved more freely. "Based on our information, both systems coexisted," Matadamas Gomora confirms. Goods, like valuable obsidian, flowed even from enemy or independent regions such as Tlaxcala and the Purépecha lands. "These goods... appear to have been above state restrictions," he added, painting a picture of a surprisingly dynamic and interconnected economy.

The highly-prized green obsidian from Pachuca, known as toltecaliztli, held particular significance. Its unique color and quality made it a favorite for priests and elites, who crafted intricate ritual objects from it. Now, thanks to meticulous work from the Templo Mayor Project team and advanced analysis, we can trace these sacred materials back to their geological birthplaces.

This remarkable study, conducted between April 2023 and May 2025, isn't just about rocks; it's about understanding the intricate lives, beliefs, and economic savvy of one of history's most fascinating empires. The humble obsidian chip, once a tool or an offering, has become a silent messenger, revealing the complex, vibrant heartbeat of ancient Tenochtitlan.