Active volcanic fumaroles are one of the most spectacular natural objects in terms of mineral diversity. The Great Tolbachik Fissure Eruption (GTFE) (Kamchatka) fumaroles are renowned for its exceptional number of mineral species. The total number of minerals that have been reliably identified from this particular locality exceeds 400, which is approximately 6.5 % of all known minerals to date. In this study, we employ a comprehensive approach (bulk chemistry, microprobe analysis, powder X-ray diffraction, HR X-ray computed tomography, and 34S, 18O, and 65Cu isotope measurements) to study the distribution of primary exhalation and secondary mineral assemblages and to reveal the driving factors responsible for the unique mineral diversity in the Yadovitaya fumarole. High oxygen fugacity, the interaction of minerals with atmospheric oxygen and water from seasonal precipitation (leading to abundant hydrated mineral associations), temperature conditions controlling the spatial distribution of mineral-forming components, gas-rock interactions, and basaltic scoria morphology perfect for the crystallization of various minerals are some of the factors revealed. The combination of these factors caused a stepwise mineralization resulting in 12 zones of the Yadovitaya fumarole with characteristic mineral assemblages. The described mineralogy of the Yadovitaya fumarole demonstrates a consistent spatial evolution of fumarolic mineral assemblages that vary in complexity, chemistry, and interaction patterns with the surrounding environment. The examination of mineralogical and geochemical data yields novel insights into the active volcanic systems that are associated with the formation of distinct oxidation-type fumaroles.