What is Hessite?
Hessite is a silver telluride ore mineral, usually grey to black and associated with gold- and silver-bearing hydrothermal deposits.
Mineralogy and structure
Reference formula: Ag2Te. Hessite is a silver telluride with temperature-dependent structural forms. Its high density and metallic appearance are characteristic, but species identification belongs with ore microscopy or analysis. Hessite belongs to the sulfides and has a monoclinic crystal system. Typical hardness is 2–3 on the Mohs scale and specific gravity is approximately 8.3–8.5.
Colour and appearance
Typical colours include lead-grey, black, silver-grey. The usual massive, granular, tabular habit and metallic lustre are useful descriptive features, but colour alone is not diagnostic.
Formation and localities
Hessite forms in or is associated with epithermal veins, telluride-rich hydrothermal deposits and oxidised silver ores. Important documented localities include Mexico, Romania, the United States, Canada, Australia and the Philippines.
Collecting and care
Keep as a labelled ore specimen; wash hands after handling and do not cut or grind unknown telluride material.
