Ferri-taramite (IMA CNMNC 2021-046), ideally ^ANa^B(CaNa)^C(Mg₃Fe)^T(Si₆Al₂)O₂₂^W(OH)₂, occurs in skarn from the Jakobsberg manganese mine, Värmland, Sweden. Associated minerals are celsian, phlogopite, aegirine-augite, andradite, hancockite, melanotekite, microcline (var. hyalophane), calcite, baryte, prehnite, macedonite and oxyplumboroméite. Conditions of formation, close to peak metamorphism (at circa 650∘C and 0.4 GPa), include silica undersaturation, a slightly peralkaline character and relatively high oxygen fugacities. Ferri-taramite forms poikiloblastic crystals up to 5 mm and is dark brownish black with a yellowish grey streak. The amphibole is brittle with an uneven to splintery fracture. Cleavage parallel to {110} is good. Hardness (Mohs) is ∼ 6, and D_calc=3.227(5) g cm⁻³. Holotype ferri-taramite has the experimental unit formula ^A(Na_0.79K_0.16Pb_0.01)_Σ0.96^B(Ca_1.26Na_0.72Mn_0.02)_Σ2^C(Mg_2.66Mn²⁺_0.58Fe²⁺_0.16Zn_0.02Fe³⁺_1.26 Al_0.26Ti_0.06)_Σ5^T(Al_1.86Si_6.14)_Σ8O₂₂^W(OH)₂, based on chemical analyses (EDS, laser-ablation ICP-MS) and spectroscopic (Mössbauer, infrared) and single-crystal X-ray diffraction data. The mineral is optically biaxial (–), with α=1.670(5), β=1.680(5) and γ=1.685(5) in white light and 2V_meas=70(10)∘ and 2V_calc=70.2∘. Ferri-taramite is distinctly pleochroic in transmitted light, with X pale yellow, Y dark brown, Z yellowish brown and absorption Y>Z>X. The eight strongest reflections in the X-ray powder pattern (d values (in Å), I_rel, hkl) are 8.44, 60, 110; 3.392, 25, 131; 3.281, 39, 240; 3.140, 100, 310; 2.816, 45, 330; 2.7104, 38, 151; 1.3654, 26, 461; and 1.4451, 33, -661. Refined unit-cell parameters from single-crystal diffraction data are a=9.89596(13), b=18.015(2), c=5.32164(7) Å, β=105.003(13)∘ and V=916.38(2) ų for Z=2. Refinement of the crystal structure yielded R=2.26 % for 2722 reflections with I_o>2σ(I). The Mn²⁺ and Fe²⁺ ions show preference for the M1 and M3 octahedrally coordinated sites, whereas Fe³⁺ is strongly ordered at M2. The A-group cations, K and Na, are split over two subsites, A(m) and A(2), respectively.