First characterization of beads and minerals from the pre-Columbian Calchaquí Valley, Northwestern Argentina

Abstract

This paper presents the first characterization of bluish and green beads and mineral debris found in three sites of the Calchaquí Valley, Northwestern Argentina, dated from Late pre-Columbian times (10 to 16th centuries). Complementary techniques for identifying elemental composition and mineral species (SEM-EDS, X-ray diffraction, Raman Spectroscopy) showed that almost all the beads found in the sites were made of turquoise, while two of them were made of chrysocolla. Regarding the mineral debris, two were identified as turquoise, two as aragonite and one as atacamite. Except the latter, all of them could have been related to local bead production. The atacamite fragment could have arrived as a residue of the turquoise extraction or intentionally selected for metallurgical purposes. The presence of these minerals suggest the potential strong connection that these sites in the Calchaqui Valley had with neighboring highlands (Puna of Salta and Catamarca) where sources of these ores are located and indicate a prevalent use of beads made of turquoise in the sites of the Calchaquí Valley in the Late and Inka periods.