Greenstone artifacts in pre-Columbian Costa Rica: from raw material to local and interregional exchanges

Area of Science:

• Archaeological science
• Material science
• Geochemistry

Background:

• Pre-Columbian societies in Costa Rica engaged in complex exchange networks.
• Greenstones were significant materials in these ancient societies.
• Understanding greenstone distribution offers insights into trade and social interactions.

Purpose of the Study:

• To investigate the distribution and abundance of greenstones used by pre-Columbian societies in Costa Rica.
• To analyze the role of local and interregional exchange systems for greenstones in the Greater Nicoya and Central Caribbean regions.
• To differentiate between locally sourced and allochthonous (foreign) greenstone materials.

Main Methods:

• Non-invasive infrared spectroscopy was used to identify mineral phases in 926 artifacts from 54 sites.
• Chemometric analyses were employed to group compositions and map their spatial distribution.
• X-ray diffraction was performed on select samples for complementary mineralogical identification.

Main Results:

• Distinct greenstone use patterns were observed in the Greater Nicoya and Central Caribbean regions.
• Locally available minerals (serpentine, tremolite-actinolite, quartz) were sourced through short-range procurement.
• Allochthonous jadeitite and albitite indicate participation in long-distance interregional exchange networks.

Conclusions:

• The study highlights the coexistence of regional and long-distance exchange networks in pre-Columbian Costa Rica.
• Regional differences in greenstone use reflect varying access to materials and exchange participation.
• Jadeite played a crucial role in connecting different lithic traditions within and beyond Costa Rica.