Mineral beads of the formative period (3500 − 1000 BP) in the atacama desert: an archeometrical and regional approach

Lapidary and bead production were two of the main related and direct practices of ancient mining activity that developed in the Atacama Desert of northern Chile. Despite acknowledging the richness of mineralogy in the region and macroscopically observing a great diversity of beads in terms of color, few studies have addressed their physical-chemical characterization to specify and accurately identify the nature of the minerals used for their production. This work synthesizes all previous analytical studies of mineral beads in the Atacama Desert and Northwestern Argentina, two closely related regions with demonstrated cultural interactions. Afterward, we precise the mineralogy of a large set of beads from archaeological contexts associated with the Formative Period (3500 − 1000 cal. BP) from different localities in the north of Chile. We described 132 mineral beads of various colors (blue, green, white, black, and ochre) and used, for the first time, Raman spectroscopy as a non-destructive technique to precise the mineralogy of 84 of them. Based on the physical-chemical characterization and spatial distribution from five different localities of the region, we confirm the wide variety of minerals used in their production and their importance in the economic interactions occurring during the Formative Period.