...Luca Bindi; Christopher J. Stanley; Yurii V. Seryotkin; Vladimir V. Bakakin; Galina A. Pal'yanova; Konstantin A. Kokh Abstract The crystal structure of the mineral uytenbogaardtite, a rare silver-gold sulfide, was solved using intensity data collected for a crystal from the type locality...

...), Dorozhnoe, Konechnoe, and Yakutskoe (Au-quartz). Dark rims around native gold are uytenbogaardtite (Ag 3 AuS 2 ) or petrovskaite (AgAuS), or a mixture of acanthite (Ag 2 S) with uytenbogaardtite or uytenbogaardtite with petrovskaite. In the ore samples from the Khopto and Ulakhan deposits, we have found...

... determined. It has been established that uytenbogaardtite is associated with native gold and hypergenesis stage minerals — goethite, hydrogoethite, or limonite replacing pyrite. The compositions of uytenbogaardtite (Ag 3 AuS 2 ), acanthite (Ag 2 S), and native gold were studied. The composition...

... analysis, compound Ag 3 Au 1 Se 0.5 S 1.5 has the structure of gold–silver sulfide Ag 3 AuS 2 (uytenbogaardtite) with space group R 3 ¯ c . The volume of this compound is 1.5% larger than that of the sulfide analog. According to powder X-ray diffraction, compounds Ag 3 AuSe 0.25 S 1.75 and Ag 3 AuSe 0.75 S...

..., acanthite, and uytenbogaardtite and Au-Ag alloys with increased fineness were established at the contacts of pyrite blocks with Au-Ag plates. The obtained results evidence the absence of solubility between FeS 2 and Au (Ag) at 500 °C. The Ag content in alloys influences the stability of pyrite...

...Fig. 5. Uytenbogaardtite associations: a , uytenbogaardtite–acanthite intergrowths and pseudomorphic development of acanthite after argentite (taken in thin section); b , intergrowths of uytenbogaardtite with sphalerite and native gold; c , heterogeneous composition of native gold...

...). The systems with an intermediate composition produce petrovskaite, uytenbogaardtite, and solid solutions Ag 2- χ Au χ S (0.5 < χ < 1). The results of experimental studies together with data on the compositions of natural gold and silver sulfides suggest that the wide variations in Au and Ag contents...

.... Primary electrum grains (light gray) replaced by Ag 2 S (dark gray)-secondary Au-rich electrum (white) and uytenbogaardtite (intermediate gray) (sample PK222). g. Primary electrum grains rimmed by uytenbogaardtite (sample PK416, level 600). h. Uytenbogaardtite intimately associated with secondary electrum...

...Fig. 3. Assemblages of ore minerals in jarosite breccia. a – c , Intergrowths of uytenbogaardtite with acanthite, native gold, and sphalerite; d , intergrowth of crystals of Au-containing polybasite (gold is seen on light etching under microscope); e – h , ore minerals from jarosite breccia...

... V). The conditions for the stability of pyrite, iron hydroxides, and gold and silver chalcogenides (petrovskaite (AgAuS) and uytenbogaardtite (Ag 3 AuS 2 )) have been estimated. It requires weakly acidic solutions with pH = 5–6 and Eh values close to zero, which ensures the stability of thiosulfate...