Archaeological obsidian from La Sierra Gorda Mexico, by PIXE

The chemical compositions of 42 obsidian pre-Hispanic artifacts from Tancama and Purísima, both archaeological sites of La Sierra Gorda Valleys, México, were analyzed by PIXE technique. These obsidians came from four sources: Sierra de Pachuca Hidalgo, Paraíso Querétaro, Ucareo Michoacán and mainly from Zacualtipán/Metzquititlán Hidalgo. According to archaeological evidences, La Sierra Gorda valleys participated in commercial exchange with other regional sites, from Classic to Post-classic periods (A.D. 300–1500).