However, what is clear is that you’re unlikely to come across any that can be traced back more than around 20 million years ago – and the same goes for other types of obsidian too.

Hundreds of obsidian artifacts have revealed where the Aztecs acquired the volcanic glass they used for tools, ornamental pieces or religious objects centuries ago — and their vast trade ...

But after the Aztec Empire defeated the Tepanecs from Azcapotzalco and began imperial expansion in 1430, obsidian types increased, showing how the Mexicas expanded their commercial networks, ...

"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 ...

Researchers analyzed 788 obsidian artifacts from Tenochtitlan, revealing that the Mexica (Aztec) Empire sourced this important material from at least eight different locations, including regions ...