Green and Golden Obsidian of “Cerro de Las Navajas”, Hidalgo (Mexico): Geoarchaeological Heritage That Deserves International Recognition

The Cerro de Las Navajas Obsidian is a volcanic rock within the Comarca Minera UNESCO Global Geopark (Hidalgo, Mexico) that possesses outstanding archaeological, cultural and geological value. It exhibits a unique green-golden macroscopic hue and was exploited and traded since ca. 250 BC, by successive Mesoamerican cultures, and until early Colonial times—ultimately recording the transition to a steel-based society. The obsidian deposit is the largest of its kind (buried) and has the longest continuous history of mining in the continent. Other green obsidians have been studied in Patagonia (Seno Otway, Chile), source for hunter-gatherers, and in Anatolia (Bingöl, Turkey), source for the Neolithic Near East. We argue here the potential of the Cerro de Las Navajas Obsidian for a heritage designation to highlight its global significance; synergies derived from an international recognition may give the opportunity to (a) put in value the multi-dimensional geoheritage of this obsidian; (b) strengthen the sense of belonging among local community; (c) require authorities to regulate obsidian mining and commercialisation, under fair trade terms, and compatible with conservation, research and responsible tourism; (d) support further research on archaeology and cultural heritage, linking geosciences with other disciplines; and (e) contribute to UNESCO Global Geoparks programme, seeking local development and sustainability. These expected achievements would be relevant given the lack of legal advisory role of geoparks in geoheritage management in Mexico.