What is Xocolatlite?
Xocolatlite is a rare manganese tellurite with a chocolate-brown colour, best known from complex oxidised tellurium deposits in Mexico and the western United States.
Mineralogy and structure
Reference formula: Ca2Mn4+(Te6+O6)2·H2O. Xocolatlite is monoclinic with the ideal formula Ca2Mn4+(Te6+O6)2·H2O. No matching public COD coordinate entry was selected, so the guide intentionally has no artificial lattice. Xocolatlite is classified with tellurites and has monoclinic crystal symmetry. Typical hardness is 2–3 on the Mohs scale and specific gravity is approximately 4.5–4.8.
Colour, lustre and habit
Typical colours include chocolate brown, dark brown, brownish black. The usual prismatic, granular, massive habit and vitreous, resinous lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Xocolatlite forms in or is associated with secondary oxidation zones of tellurium-rich gold-silver deposits. Important documented localities include the Moctezuma Mine in Sonora, Mexico, Nevada, Utah and other rare tellurium districts.
The chocolate-brown tellurite collectors seek
Xocolatlite is a memorable cabinet mineral because its colour is unusually distinctive and its name reflects the Mexican type locality. Provenance and safe handling are part of the story.
Collecting and care
Tellurium-bearing and soft: keep sealed and dry, avoid dust, acids and grinding, and wash hands after handling.
