Abstract <p>The article is devoted to the assessment of the formation conditions of the Yugo-Konevskoe and the Porokhovskoe deposits, which belong to the same ore zone; are localized in granites and in a metamorphosed volcanogenic-sedimentary sequence, respectively; and are separated by a large thrust. According to the results of the study of fluid inclusions in quartz, the formation of quartz ± fluorite ± muscovite veins with hubnerite at both deposits took place under similar conditions, at minimum true temperatures of 245–540°C and a pressure of ∼350 bar, from carbon-dioxide–water fluids of sodium-chloride composition with an admixture of K, Ca, and Mg carbonates, with a salt concentration from 0.54 to 16.13 wt % NaCl-eq. CO₂ predominates in the gas phase, and impurities of CH₄, N₂, and H₂S are recorded. The similarity of the mineral composition, fluid and muscovite composition in the ore veins indicates a single source of ore-bearing fluid for both deposits and an insignificant influence of the host rocks on it. The simultaneous presence of low-mineralized inclusions and inclusions with a solid phase indicates a phase separation, which is more pronounced at the Yugo-Konevskoe deposit. Late quartz in the skarns of the Porokhovskoe deposit was formed at lower temperatures than the ore veins and from solutions that contained a sulfate component, reflecting the probable assimilation of limestones from the host strata during skarnification. Low pressures estimated from fluid inclusions are due to the formation of ore veins as a result of brittle deformations of consolidated rocks. The obtained <i>PTX</i> parameters of the fluids correspond to those characteristic of greisen formation objects, falling into the relatively low-pressure and low-temperature region.</p>