New Almaden hydrothermal deposition of cinnabar from deep within the earth is found in a gangue of silica-carbonate rock formed locally by hydrothermal alteration of serpentine. The Guadalupe mine produced about 10% as much mercury as the New Almaden. There are several smaller mines in the mining district, but their ore production was not significant. The only significant quicksilver ore is cinnabar; other sulfides are present in small quantities. Mining, other than a single placer deposit of cinnabar, was underground. There is a high probability of undiscovered high-grade ore which could be found and exploited using modern techniques. Mining operations resulted in
Ore genesis classified hydrothermal deposits as "hypothermal", "mesothermal", "epithermal", and "telethermal". Epithermal deposits are hydrothermal ore deposits formed at low temperatures (50-200 °C) near the Earth´s surface (<1500 m), that fill veins, breccias, and stockworks. The age of formation of epithermal deposits in México is currently being investigated. "As they require the conjunction of specific environmental conditions to form, particular mineral deposit types tend to occupy specific geodynamic niches," therefore, this page has been organised by metal commodity. It is also possible to organise theories the other way, namely according to geological criteria of formation. Often ores of the same metal can