The paper presents the results of a complex study of native gold from nine placers of the Murzinka group in the Middle Urals. Morphological features, chemical composition, and internal structure of native gold, as well as mineral inclusions within it, are described in detail. Based on the analysis of morphological characteristics and the gold particles rounding degree, the proximity of lode gold sources is inferred ranging from several hundred meters to the first few kilometers. Three types of native gold were identified according to the chemical composition and mineral inclusions. Type I (the predominant type) is characterized by high fineness with Ag and Hg admixture and inclusions of pyrite, chalcopyrite, galena, molybdenite, and petzite. The variation in admixture content within this type allows the definition of subtypes; their distribution in placers reflects the zoning of lode quartz gold mineralization. Type II is distinguished by elevated copper contents and bornite inclusions; Type III is defined by high Ag contents. Lode sources for the different gold types have been identified: for Type I, a quartz gold lode deposits; for Type II, precious metal mineralization in the gabbroids of the Pavdinsky massif. Application of the electron backscatter diffraction (EBSD) technique enabled a detailed characterization of the internal structure of gold particles. The observed high fineness intergranular veins and intergrowths of gold with minerals of the rhabdophane group suggest that native gold was located in the supergene zone during the period of active weathering crust development in the Upper Mesozoic and Palaeogene. It is established that the placer system in the Murzinka River basin formed during the Neogene-Quaternary period, primarily due to lode quartz gold mineralization. The obtained data allow the localization of prospective areas for the exploration of lode gold deposits and expand the understanding of the region’s metallogenic potential.

The article presents the first data on biotite-hornblende lamprophyres discovered at the Peshchernoe gold deposit. We consider the geological position of lamprophyre dikes in the deposit structure and the relationship of these rocks with tectonically weakened and mineralized zones. The data on the structural position of mineralized zones, faults, dike bodies, metasomatic halos, and host volcanogenic-sedimentary rocks confirm the tectonic nature of the Peshchernoe deposit alteration system. Lamprophyre dikes are pre-ore, as evidenced by the superimposed metasomatic mineral associations. We assume that dikes of andesitic rocks, lamprophyres, and subsequently hydrothermal fluids, including ore-bearing ones, were intruded along the fault zone of northeastern strike at different geological times. The description of mineralogical and chemical transformations of lamprophyres, which occurred as a result of alteration, is given. Two stages of metasomatism are distinguished: carbon dioxide (beresitization-listvenitization) and subsequent alkaline (sodic metasomatism). During carbon dioxide metasomatism, dark-coloured minerals are replaced by chlorite, albitization and sericitization of plagioclase occur, and ferruginous dolomite is formed under the influence of a significant supply of CO2. Alkaline (sodic) metasomatism is superimposed on the mineral metasomatic paragenesis of the first stage. We consider metasomatic zoning during sodic metasomatism, manifested in one of the spessartite dikes. Chlorite and relics of magmatic dark-coloured minerals are replaced by magnesite, the supply of Na leads to the appearance of newly formed albite, and the supply of S leads to the formation of pyrite, which concentrates iron from other minerals. As a result of the sodic metasomatism, iron content in carbonates decreases in the direction from the outer metasomatic zone to the inner one. We conclude that it was the alkaline-sulphide sodium solutions that performed the ore-bearing function, and beresitization and listvenitization prepared a favourable environment for ore deposition.

The results of the chemical composition of platinum minerals from ore body and placers of Nizhni Tagil massif of Ural Platinum Belt are summarized in the given article. Peculiar properties of the chemical composition of the platinum group minerals from ore body and placers are established and described. X-ray analysis data of the most common mineral species was ob-tained and the internal structure of granular aggregates and mono crystals was studied with due regard to the various irregularities.

In 1826 two unique icons were delivered to Saint Petersburg Mining Cadet corps from Zlatoust. They were named composed icons because of their background composed of different Ural stones. These icons have become the objects of the historical analysis which results are presented in this article. The documents which are kept in the Saint Petersburg and Zlatoust archives served as a basis for icons history reconstruction. The article describes the story of malachite and corund blocks delivery to the museum of the Cadet corps. This story is based on the information which was found in the one of archival documents.