Where Did the Aztecs Get Their Turquoise?

New analysis shows the blue-green mineral found in Aztec art was likely mined in Mexico, not the American Southwest as previously believed



Turquoise Mosaic
(Oliver Santana/Editorial Rai’ ces)

By Jason Daley
smithsonian.com
June 15, 2018

The American Southwest, including Arizona and New Mexico, is chock-full of ancient turquoise mines. Mesoamerica, including southern Mexico and Central America, however, have few if any. So researchers long believed that the Aztec empire and Mixtec cultures must have traded with peoples of the Southwest for the culturally important blue-green mineral. But Nicholas St. Fleur at The New York Times reveals a new study now questions that bedrock assumption.

According to the paper, published in the journal Science Advances, between the 1970s and 1990s, archaeologists had put their assumptions to the test though chemical analysis of the Aztec turquoise, which revealed that the turquoise came from the northern mines. In the new study, however, researchers decided to take another look using more modern techniques, analyzing the lead and strontium isotopes in turquoise mosaics from both the Aztec Temple of Mayor in Mexico City as well as Mixteca tiles held by the Smithsonian’s National Museum of the American Indian.

After shaving the edges of the tiles, the researchers dissolved them in acid, then looked for the isotopic ratios, which act as a geographic fingerprint. What they found is that the chemical signatures of the turquoise matched the geology of Mesoamerica, not the Southwest. That suggested that the Aztec and Mixtec got their supplies of the blue-green rock locally, not from distant mines.

Lead author Alyson Thibodeau from Dickinson College in Pennsylvania tells St. Fleur she was working late one night when she got the results. “I saw the number pop up and I’m pretty sure I did a dance around the lab,” she says. “Not only do they have isotopic signatures that are absolutely consistent with the geology of Mesoamerica, but they are completely different from the isotopic signatures of the Southwestern turquoise deposits and artifacts that we have seen so far.”

Read more: https://www.smithsonianmag.com/smart-news/aztec-turquoise-was-probably-locally-sourced-180969375/#bG73zv5ig5QXkMcj.99