The new mineral ziminaite, ideally Fe³⁺VO₄, was found in fumarole sublimates at the Bezymyannyi volcano, Kamchatka, Russia. Ziminaite occurs as lamellar, tabular or flattened prismatic crystals up to 10 × 30 × 50 μm typically epitaxially overgrowing koksharovite, and as aggregates (up to 0.15 mm) associated with bannermanite in cavities in volcanic scoria. The mineral is translucent, yellowish-brown with an adamantine luster. The calculated density is 3.45 g cm^{− 3}. In reflected light, ziminaite is light grey. Bireflectance is weak, internal reflections are deep yellow. The reflectance values [R_max–R_min, % (λ, nm)] are: 17.7–16.3 (470), 15.7–14.1 (546), 15.1–13.8 (589), 14.7–13.6 (650). Chemical composition (wt%) is: MgO 2.20, CaO 0.01, Al₂O₃ 7.81, Fe₂O₃ 27.18, TiO₂ 4.50, SiO₂ 0.26, P₂O₅ 0.09, V₂O₅ 57.01, total 99.06. The empirical formula, based on 24 O atoms, is: (Fe^{3 +} _3.29Al_1.48Ti_0.54Mg_0.53)_Σ5.84(V_6.05Si_0.04P_0.01)_Σ6.10O₂₄ (Z = 1). Ziminaite is triclinic, P1 ¯ , a 8.012(4), b 9.345(5), c 6.678(3) Å, α 106.992(10), β 101.547(8), γ 96.594(11)º, V 460.4(4) ų, Z = 6. The strongest reflections of the powder X-ray diffraction pattern [d,Å(I)(hkl)] are: 3.751(17)(1–21, 12 − 1), 3.539(86)(120), 3.270(67)(01–2), 3.209(100)(2–20), 3.090(20)(2–11, 002), 3.041(18)(03 − 1, 02–2), 2.934(14)(12 − 2, 030) and 1.665(24)(023, 12 − 4). The crystal structure, solved from single-crystal data (R₁ = 0.085), is based upon heteropolyhedral framework built by VO₄ tetrahedra and Fe³⁺-centred octahedra and five-fold polyhedra. Ziminaite belongs to the howardevansite group being its first member without species-defining uni- or divalent cations and with all large cation sites vacant. The mineral is named after the Zimina volcano situated near the discovery locality.