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 rock within the Comarca Minera, Hidalgo UNESCO Global Geopark, 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. It is the largest deposit of its kind and the longest historical exploited site in the continent. We argue here the potential of this particular obsidian for a heritage designation that highlights its global significance; synergies derived from an international recognition may offer the chance (a) to put in value the multi-dimensional geoheritage of this obsidian, (b) to strengthen the sense of belonging among local community, (c) to require authorities to regulate obsidian mining and commercialization, under fair trade terms and compatible with conservation, research and responsible tourism, (d) to support further research on archaeology and cultural heritage linking geosciences with other disciplines, and (e) to contribute to UNESCO Global Geoparks program’s aims seeking local development and sustainability. The two last expected achievements would be relevant given the lack of legal advisory role of geoparks in geoheritage management in Mexico and its geoconservation community.