ABSTRACT
Microscopic gold is divided into 8 main groups (inclusions in sulfides, inclusions in association with other sulfide inclusions, in microfissures, in caverns, overgrowth on sulfide surfaces, as a “free gold”, within pseudomorphs, and as remnants in metallurgical slags) and 17 subgroups. Electrum, native gold and less commonly maldonite are representing Au minerals. They are in close association with Bi (native bismuth, bismuthine) and Te minerals (hessite, hedleyite, pilsenite and gustavite). Microscopic gold, beside Ag and Bi admixtures, may contain admixtures of Cu, Te and Se traces as well. In most of the studied cases, a few generations of microscopic gold occur. The oldest ones in the form of inclusions in sulfides represents “chemically bound gold”. Younger generations in various forms, such as microveinlets, “free gold” or filling microfissures in ore minerals or gangue. Microscopic gold was also recognised within colloform structures of hydrated Fe-oxide pseudomorphs after Au-bearing sulfides and as remnants within cavities of metallurgical slags.
