Anhydrous sulfate minerals are abundant in the active fumaroles with highly oxidizing conditions on the scoria cones of the Tolbachik volcano. The mineral itelmenite, ideally Na₂CuMg₂(SO₄)₄, containing isomorphous admixture of Zn, was described in 2018, whereas glikinite, ideally Zn₃O(SO₄)₂, was described in 2020. Synthetic analogs of both minerals were obtained during studies of phase formation in the Na₂SO₄–CuSO₄–MgSO₄–(ZnSO₄) systems which lead to essentially different results. Solid-state syntheses resulted in formation of several compounds previously known as minerals only. Both Zn- and Mg-containing analogs of itelmenite were prepared and exhibit slight deviations from the ideal Na₂CuM₂(SO₄)₄ stoichiometry. The Mg compound could be prepared single-phase which allowed the study of its thermal expansion and IR spectroscopy. Na₂CuMg₂(SO₄)₄ and Na₂CuZn₂(SO₄)₄ were evaluated for Na⁺-ion diffusion. For the Zn compound, several by-products were observed which are synthetic analogs of puninite Na₂Cu₃O(SO₄)₂, as well as hermannjahnite CuZn(SO₄)₂ and glikinite-type (Zn,Cu)₃O(SO₄)₂. All of them were prepared via solid-state reactions in open systems. The Na₂CuMg₂(SO₄)₄, Na₂CuZn₂(SO₄)₄ and (Zn,Cu)₃O(SO₄)₂ were structurally characterized by the single-crystal XRD. In the Zn-bearing system, the admixture of Cu²⁺ likely controls the formation of itelmenite-type and glikinite-type phases. The results of the experiments allowed to deduce possible scenarios of the formation processes of itelmenite and some other endemic fumarolic minerals. Our study shows that outstanding mineralogical diversity observed in the fumaroles of the Tolbachik scoria cones is not only due to the formation from the gas enriched by transition metals and involves also intensive exchange with the host basaltic scoria. Similar processes seem also to be responsible for the recrystallization of many other mineral species observed in high-temperature fumaroles resulted from the recent eruptions.