The ores occur within Palaeocene to Eocene calcarenites beneath a Pliocene-Pleistocene quartz latite of the Mount Amiata volcanic series. Minor antimony mineralization is associated with the mercury ores.
Major Minerals:
Cinnabar
Minor Minerals:
Marcasite, pyrite
Trace Minerals:
Include stibnite, realgar, native mercury
Textures:
Cinnabar forms polycrystalline, often bladed, aggregates
