Original paper

Mineralogy of the Niederschlema-Alberoda U - Se-polymetallic deposit, Erzgebirge, Germany. II: Hessite, Ag2Te, and native Te (?), the first tellurium minerals

Förster, H.J.


Hessite, Ag2Te, and native tellurium (?) constitute two, previously unknown tellurium species within the complex mineral assemblage at Niederschlema-Alberoda, Erzgebirge, Germany. Hessite is always intimately associated with clausthalite and has a composition close to ideal stoichiometry. The mean empirical formula is (Ag1.98Sb0.01)1.99(Te0.96Se0.05)1.01. Paragenetic relations and thermodynamic data suggest that hessite crystallized in equilibrium with clausthalite, berzelianite, and tiemannite under conditions of almost identical, high fugacitities of Se2 and Te2, which very locally were approached in the main selenide stage of Jurassic age. Native tellurium (?) formed as replacement product of hessite. Niederschlema-Alberoda provides the first record of hessite from an uranium deposit worldwide. Hessite and native Te are the first tellurium minerals reported from the Erzgebirge metallogenic province.


hessitenative telluriumselenium and tellurium fugacitiesuranium depositniederschlema-alberodaerzgebirgegermany