The discovery also sheds light on how the Aztec society evolved — introducing more standardized religion and control before the empire fell in 1520 — by showing how obsidian use changed over time.

The discovery also sheds light on how the Aztec society evolved — introducing more standardized religion and control before the empire fell in 1521 — by showing how obsidian use changed over time.

The Aztecs didn't discover obsidian. It was already the most common raw material in Mesoamerica when they arrived in the ...