Oxy-foitite, □(Fe²⁺Al₂)Al₆(Si₆O₁₈)(BO₃)₃(OH)₃O, is a new mineral of the tourmaline supergroup. It occurs in high-grade migmatitic gneisses of pelitic composition at the Cooma metamorphic Complex (New South Wales, Australia), in association with muscovite, K-feldspar and quartz. Crystals are black with a vitreous luster, sub-conchoidal fracture and gray streak. Oxy-foitite has a Mohs hardness of ∼7, and has a calculated density of 3.143 g/cm³. In plane-polarized light, oxy-foitite is pleochroic (O= dark brown and E = pale brown), uniaxial negative. Oxy-foitite belongs to the trigonal crystal system, space group R3m, a = 15.9387(3) Å, c = 7.1507(1)Å and V = 1573.20(6)ų,Z = 3. The crystal structure of oxy-foitite was refined to R1 = 1.48% using 3247 unique reflections from single-crystal X-ray diffraction using MoKα radiation. Crystal-chemical analysis resulted in the empirical structural formula: ^X(□_0.53Na_0.45Ca_0.01K_0.01)_Σ1.00^Y(Al_1.53Fe²⁺_1.16Mg_0.22Mn²⁺_0.05Zn_0.01Ti⁴⁺_0.03)_Σ3.00^Z(Al_5.47Fe³⁺_0.14Mg_0.39)_Σ6.00[(Si_5.89Al_0.11)_Σ6.00O₁₈](BO₃)₃^V(OH)₃^W[O_0.57F_0.04(OH)_0.39]_Σ1.00. Oxy-foitite belongs to the X-site vacant group of the tourmaline-supergroup minerals, and shows chemical relationships with foitite through the substitution ^YAl³⁺+^WO^2-→^YFe²⁺+^W(OH)^1–.

Zinkgruvanite, ideally Ba4Mn2+4Fe3+2(Si2O7)2(SO4)2O2(OH)2, is a new member of the ericssonite group, found in Ba-rich drill core samples from a sphalerite+galena- and diopside-rich metatuffite succession from the Zinkgruvan mine, Örebro county, Sweden. Zinkgruvanite is associated with massive baryte, barytocalcite, diopside and minor witherite, cerchiaraite-(Al) and sulfide minerals. It occurs as subhedral to euhedral flattened and elongated crystals up to 4 mm. It is almost black, semi-opaque with a dark brown streak. The luster is vitreous to sub-adamantine on crystal faces, resinous on fractures. The mineral is brittle with an uneven fracture. VHN100 = 539 and HMohs ~4½. In thin fragments, it is reddish-black, translucent and optically biaxial (+), 2Vz > 70°. Pleochroism is strong, deep brown-red (E ⊥ {001} cleavage) to olive-pale brown. Chemical point analyses by WDS-EPMA together with iron valencies determined from Mössbauer spectroscopy, yielded the empirical formula (based on 26 O+OH+F+Cl anions): (Ba4.02Na0.03)Σ4.05(Mn1.79Fe2+1.56Fe3+0.42Mg0.14Ca0.10Ni0.01Zn0.01)Σ4.03 (Fe3+1.74Ti0.20Al0.06)Σ2.00Si4(S1.61Si0.32P0.07)Σ1.99O24(OH1.63Cl0.29F0.08)Σ2.00. The mineral is triclinic, space group P–1, with unit-cell parameters a = 5.3982(1) Å, b = 7.0237(1) Å, c = 14.8108(4) Å, α = 98.256(2)º, β = 93.379(2)º, γ = 89.985(2)º and V = 554.75(2) Å3 for Z = 1. The eight strongest X-ray powder diffraction lines are [d Å (I%; hkl)]: 3.508 (70; 103), 2.980(70; 11–4), 2.814 (68; 1–22), 2.777 (70; 121), 2.699 (714; 200), 2.680 (68; 20–1), 2.125 (100; 124, 204), 2.107 (96; –221). The crystal structure (R1 = 0.0379 for 3204 reflections) is an array of TS (titanium silicate) blocks alternating with intermediate blocks. The TS blocks consist of HOH sheets (H = heteropolyhedral, O = octahedral) parallel to (001). In the O sheet, the Mn2+-dominant MO(1,2,3) sites give ideally Mn2+4 pfu. In the H sheet, the Fe3+-dominant MH sites and AP(1) sites give ideally Fe3+2Ba2 pfu. In the intermediate block, SO4 oxyanions and eleven coordinated Ba atoms give ideally 2 × SO4Ba pfu. Zinkgruvanite is related to ericssonite and ferro-ericssonite in having the same topology and type of linkage of layers in the TS block. Zinkgruvanite is also closely compositionally related to yoshimuraite, Ba4Mn4Ti2(Si2O7)2(PO4)2O2(OH)2, via the coupled heterovalent substitution 2 Ti4+ + 2 (PO4)3- →2 Fe3+ + 2 (SO4)2-, but presents a different type of linkage. The new mineral probably formed during a late stage of regional metamorphism of a Ba-enriched, syngenetic protolith, involving locally generated oxidized fluids of high salinity.

Mineral evolution is concerned with the timing of mineral occurrences, such as the earliest reported occurrences in the geologic record. Minerals containing essential Li have not been reported from rocks older than ca. 3000 Ma, thus the lithian tourmaline (fluor-elbaite) and mica (lepidolite) assemblage from a pegmatite near Zishineni associated with the ca. 3000Ma Sinceni Pluton presents unusual interest. Fluor-elbaite (0.75–0.98 F per formula unit) forms green crystals up to 50mm long. Spindle stage measurements give ω = 1.652(1), ε = 1.627(1) (589.3 nm). Optical absorption spectroscopy shows Fe and Mn are divalent; infra-red spectroscopy demonstrates the presence of Li and indicates the presence of (OH) at both the (OH) sites. Electron microprobe analysis of 330 points on several prisms, the largest of which is zoned in Fe and Ca, gives the following average and standard deviations in wt%: SiO₂ 37.29 (0.26), TiO₂ 0.05 (0.05), Al₂O₃ 38.14 (0.35), Cr₂O₃ 0 (0.02), MgO 0.02 (0.01), MnO 3.57 (0.25), FeO 2.48 (0.60), Na₂O 2.48 (0.09), K₂O 0.03 (0.12), CaO 0.77 (0.21), F 1.80 (0.11), Cl 0 (0.01) wt%. Nuclear reaction analyses gave Li₂O 0.91 (0.04) and B₂O₃ 10.55 (0.45). The empirical formula of fluor-elbaite was determined by integrating crystal-chemical data from electron microprobe analysis, nuclear reaction analysis, crystal structure refinement using X-ray diffraction, infra-red and optical absorption spectroscopy:X(□_0.09Na_0.77K_0.01Ca_0.13)_Σ1.00 Y(□_0.35Li_0.59Mn_²⁺0.49Fe²⁺_0.33Al_1.23Ti_0.01)_Σ3.00Al₆(Si₆O₁₈)(BO₃)₃^O3(OH)₃^O1[F_0.92(OH)_0.08]_Σ1.00. The crystal structure of fluor-elbaite was refined to statistical indices R1 for 1454 reflections ∼2% using MoKa X-ray intensity data. Structural data confirm the presence of significant vacancies at the Y site. Micas include lepidolite in flakes several millimeters across that are veined and overgrown by fine-grainedmuscovite. Silica and (FeO+MnO) increase, and Al decreases with F, all giving tight linear fits for both micas taken together, suggesting bothmicas can be regarded as interstratified muscovite and lithium mica consisting of 35.2 wt% masutomilite containing nearly equal amounts of Mn and Fe, 52.8 wt% polylithionite and 11.9 wt% trilithionite. Muscovite and lepidolite contain <0.2 wt% and 0.7–2.25 wt% Cs₂O and 1.0–1.1 wt% and 1.4–1.5wt% Rb₂O, respectively. Other minerals include spessartine (e.g., Sps₉₃Alm₄Grs₃) in scattered grains up to 0.5mm across and monazite.Oxides occur sparsely in muscovite, rarely in lepidolite, as grains up to 11 mm long, including fluorcalciomicrolite, columbite-(Mn) withNb>Ta, hübnerite(?) and a possible Pb-bearing microlite (Ta>Nb). The oxides, together with the muscovite, are interpreted to be related to later hydrothermal reworking of the primary lepidolite–fluorelbaite assemblage. Given the 2990 ± 43MaRb–Sr isochron and 3074 ± 4Ma evaporation Pb–Pb ages reported for the Sinceni Pluton and Rb/Sr mineral ages ranging from 2906 ± 31Ma to 3072 ± 33Ma reported for the pegmatites, the fluor-elbaite–cesian lepidolite–fluorcalciomicrolite-bearing pegmatite is the first reported occurrence of a lithian tourmaline and lepidolite in the geologic record, as well as one of the two earliest known examples of the lithium–cesium–tantalum (LCT) family of pegmatites. The Sinceni magma is most plausibly derived from a metasedimentary source by intrusion of hot mantle melts into the crust from below, thereby indicating that a “mature” continental crust existed in the Kaapvaal craton at ca. 3000 Ma.

Delhuyarite-(Ce) is a new mineral (IMA no. 2016-091) with ideal formula Ce₄Mg(Fe³⁺₂W)□(Si₂O₇)₂O₆(OH)₂. It is named after Juan and Fausto de Elhuyar (Delhuyar), chemists and metallurgists, who in 1783 isolated tungsten metal for the first time.  Associated minerals in the only known sample, from the Nya Bastnäs Fe–Cu–REE deposit (Västmanland, Sweden), include cerite-(Ce), tremolite‒actinolite, percleveite-(Ce), bastnäsite-(Ce), ferriallanite-(Ce), törnebohmite-(Ce), magnetite, chalcopyrite, quartz and scheelite. Delhuyarite-(Ce), which forms subhedral crystals up to 0.3mm long, is brown–black with a dark brown streak and translucent with an adamantine lustre. It is pleochroic in black to rust red and optically biaxial (-). Calculated density and mean refractive index are 5.20 g·cm^-3 and 1.94, respectively. Chemical analyses (electron microprobe) gave (in wt%) La₂O₃ 14.58, Ce₂O₃ 23.29, Pr₂O₃ 1.89, Nd₂O₃ 6.13, Sm₂O₃ 0.74, Gd₂O₃ 0.37, Dy₂O₃ 0.03, Er₂O₃ 0.04, Yb₂O₃ 0.12, Y₂O3 0.22, CaO 0.76, Fe₂O₃ 12.86, MgO 2.43, Al₂O₃ 0.73, SiO₂ 18.16, TiO₂ 0.09, WO₃ 15.53, H₂O_calc 1.33, F 0.05, Cl 0.03, O=(F, Cl) 0.03, sum 99.35, corresponding to an empirical formula: (Ce_1.89La_1.19Nd_0.48Pr_0.15Sm_0.06Gd_0.03Y_0.03Ca_0.18)_Σ4.01(Fe³⁺_2.14W_0.89Mg_0.80Al_0.19Ti_0.02)_Σ4.04Si_4.01O₂₀(OH_1.96F_0.04)_Σ2, based on 22 O atoms per formula unit (apfu). The presence of H₂O is confirmed by IR-spectroscopy, from a strong absorption band at 3495 cm^-1. Delhuyarite-(Ce) is monoclinic, space group C2/m, with unit-cell parameters a =13.6020(6)Å, b = 5.7445(3)Å, c = 10.9996(5)Å, β = 100.721(4)°, V = 844.47 (6)ų and Z = 2 (data for natural crystal). The crystal structure was refined to an R1 index of 3.9% (natural crystal) and 1.8% (annealed). Delhuyarite-(Ce) has the same structural topology as chevkinite subgroup minerals, e.g. chevkinite-(Ce). It is the only mineral of the group with a significant content of W⁶⁺ = 0.89 apfu. In delhuyarite-(Ce), Mg is dominant at the M1 site as in polyakovite-(Ce); the composition of the M2, M3 and M4 sites is [(Fe³⁺2W)□], with M2 being 50% vacant.

Ulfanderssonite-(Ce) is a new mineral (IMA 2016-107) from the long-abandoned Malmkärra iron mine, one of the Bastnäs-type Fe-rare earth element (REE) deposits in the Bergslagen ore region, central Sweden. It is named for Ulf B. Andersson, a Swedish geologist and petrologist. In the type specimen, the mineral occurs with västmanlandite-(Ce), bastnäsite-(Ce), phlogopite, talc, magnetite, pyrite, fluorbritholite-(Ce) and scheelite. Ulfanderssonite-(Ce) forms pinkish, translucent subhedral grains, 100–300 mm, in aggregates up to 2 mm. Fracture is uneven, and there is an indistinct cleavage parallel (001). Mohs' hardness is 5−6, d_calc= 4.97 g·cm^-3. Optically, ulfanderssonite-(Ce) is nonpleochroic, biaxial negative, with 2V_meas =55° and n_calc=1.82. The ideal composition is Ce₁₅CaMg₂(SiO₄)₁₀(SiO₃OH)(OH,F)₅Cl₃. EMP and LA-ICP-MS chemical analyses yielded (in wt%) La₂O₃ 11.87, Ce₂O₃ 30.98, Pr₂O₃ 3.99, Nd₂O₃ 17.14, Sm₂O₃ 2.81, Eu₂O₃ 0.18, Gd₂O₃ 1.15, Dy₂O₃ 0.30, Tb₂O₃ 0.10, Y₂O₃ 1.11, CaO 2.26, FeO 0.02, MgO 1.97, P₂O₅ 0.08 SiO₂ 19.13, H₂O_calc 1.07, F 1.09, Cl 2.89, O=(F, Cl) -1.10, sum 97.04. The five strongest powder X-ray diffraction lines are [I (%) d_obs(Å) (hkl)]: 100 2.948 (-421), 47 2.923 (204), 32 2.660 (-225), 26 3.524 (40-1), 25 1.7601 (6-23). Ulfanderssonite-(Ce) is monoclinic, Cm, with a =14.1403(8), b = 10.7430(7), c = 15.498(1) Å, β = 106.615(6)° and V = 2256.0(2) ų for Z = 2. The crystal structure has been solved by direct methods and refined to R₁ = 2.97% for 5280 observed reflections. It consists of a regular alternation of two layers, designated A and B, along the c-axis: A (ca. 9 Å thickness), with composition [(Ce₈Ca)MgSi_7­O₂₂(OH,F)₄]⁸⁺, and B (ca. 6.5 Å), with composition [Ce₇Mg­Si₄O₂₁(OH,F)₂Cl₃]^8-; the A layer is topologically and chemically closely related to cerite-(Ce). A FTIR spectrum shows strong absorption in the region 2850−3650 cm^-1, related to the presence of O-H stretching bands. Ulfanderssonite-(Ce) is interpreted as a primary mineral at the deposit, along with the more common fluorbritholite-(Ce), formed by a magmatic-hydrothermal fluid with REE, Si, F and Cl ion complexes reacting with dolomite marble. The presence of ulfanderssonite-(Ce) is direct evidence of a Cl-rich mineral-forming aqueous solution, normally not reflected in the composition of skarn minerals in Bastnäs-type deposits.

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.

Hjalmarite, ideally ^ANa^B(NaMn)^CMg₅^TSi₈O₂₂^W(OH)₂, is a new root-name member of the amphibole supergroup, discovered in skarn from the Långban Fe-Mn-(Ba-As-Pb-Sb-Be-B) deposit, Filipstad, Värmland, Sweden (IMA-CNMNC 2017-070). It occurs closely associated with mainly rhodonite and quartz. It is grayish white with vitreous luster and non-fluorescent. The crystals are up to 5 mm in length and display splintery fracture and perfect cleavage along {110}. Hjalmarite is colorless (non-pleochroic) in thin section and optically biaxial (-), with α = 1.620(5), β = 1.630(5), γ = 1.640(5). The calculated density is 3.12 Mg/m³. Average VHN₁₀₀ is 782, corresponding to circa 5½ Mohs. An empirical formula, derived from EPMA analyses in combination with crystal structure refinements, is (Na_0.84K_0.16)_Σ1(Na_1.01Mn_0.55Ca_0.43Sr_0.01) _Σ2(Mg_3.83Mn_1.16Al_0.01) _Σ5(Si_7.99Al_0.01) _Σ8O₂₂(OH_1.92F_0.08)_Σ2. An infra-red spectrum of hjalmarite shows distinct absorption bands at 3673 cm^-1 and 3731 cm^-1 polarized in the α direction. The eight strongest Bragg peaks in the powder X-ray diffraction pattern are [d (Å), I (%), (hkl)]: 3.164, 100, (310); 2.837, 50, (330); 8.50, 44, (110); 3.302; 40, (240); 1.670, 34, (461); 1.448, 32, (-661); 2.727, 30, (151); 2.183, 18 (261).

Single-crystal X-ray diffraction data were collected at 298 K and 180 K. The crystal structure was refined in space group C2/m to R1=2.6% [I>2(I)], with observed unit-cell parameters a = 9.9113(3), b = 18.1361(4), c = 5.2831(5) Å, β=103.658(5)° and V = 922.80(9) ų at ambient temperature. The A and M(4) sites split into A(m) (K⁺), A(2) (Na⁺), and M(4’) (Mn²⁺) subsites, respectively. Among the octahedrally coordinated C group cations, Mn²⁺ orders strongly at the M(2) site. No significant violation of C2/m symmetry or change in the structure topology is detected at low temperature (R₁=2.1%). The hjalmarite-bearing skarn formed at peak regional metamorphism, T  ≥ 600°C, at conditions of high SiO₂ activity and relatively low oxygen fugacity. The mineral name honors the Swedish geologist and mineralogist S.A. Hjalmar Sjögren (1856–1922).

Monteneveite, ideally Ca₃Sb⁵⁺₂(Fe³⁺₂Fe²⁺)O₁₂, is a new member of the garnet supergroup (IMA2018-060). The mineral was discovered in a small specimen belonging to the Swedish Museum of Natural History coming from the now abandoned Monteneve Pb–Zn mine in Passiria Valley, Bolzano Province, Alto Adige (South Tyrol), Italy. The specimen consists of mainly magnetite, sphalerite, tetrahedrite-(Fe) and oxycalcioroméite. Monteneveite occurs as black, subhedral crystals with adamantine lustre. They are equidimensionaland up to 400 μm in size, with a subconchoidal fracture. Monteneveite is opaque, grey in reflected light,and isotropic under crossed polars. Measured reflectance values (%) at the four COM wavelengths are 12.6 (470 nm), 12.0 (546 nm), 11.6 (589 nm) and 11.4 (650 nm). The Vickers hardness (VHN₁₀₀) is 1141 kg mm^-2, corresponding to H = 6.5–7, and the calculated density is 4.72(1) g cm^-3. A mean of 10 electron microprobe analyses gave (wt %) CaO 23.67, FeO 3.75, Fe₂O₃ 29.54, Sb₂O₅ 39.81, SnO₂ 2.22, ZnO 2.29, MgO 0.15, MnO 0.03 and CoO 0.03. The crystal chemical formula calculated on the basis of a total of eight cations and 12 anions, and taking into account the available structural and spectroscopic data, is (Ca_2.97Mg_0.03)_Σ=3.00(Sb⁵⁺_1.73Sn⁴⁺_0.10Fe³⁺_0.17)_Σ=2.00(Fe³⁺_2:43Fe²⁺_0.37Zn_0.20)_Σ=3.00O₁₂. The most significant chemical variations encounteredin the sample are related to a substitution of the type ^YSn⁴⁺ + ^ZFe^{3+  Y}Sb⁵⁺ + ^ZFe²⁺. Mössbauer data obtained at RT and 77K indicate the presence of tetrahedrally coordinated Fe²⁺. Raman spectroscopy demonstrates that there is no measurable hydrogarnet component in monteneveite. The six strongest Bragg peaks in the powder X-ray diffraction pattern are [d (Å), I (%), (hkl)]: 4.45, 100, (220); 3.147, 60, (400); 2.814, 40, (420); 2.571, 80, (422); 1.993, 40, (620); 1.683, 60, (642). Monteneveite is cubic, space group Ia-3d, with a =12.6093(2) Å, V = 2004.8(1)ų, and Z = 8. The crystal structure was refined up to R1 = 0.0197 for 305 reflections with F_o > 4σ (F_o) and 19 parameters. Monteneveite is related to the other Ca-, Sb- and Fe-bearing, nominally Si-free members of the bitikleite group, but it differs in that it is the only known garnet species with mixed trivalent and divalent cations (2:1) at the tetrahedral Z site. Textural and mineralogical evidence suggests that monteneveite formed during peak metamorphism (at ca. 600 ºC) during partial breakdown of tetrahedrite-(Fe) by reactions with carbonate, under relatively oxidizingconditions. The mineral is named after the type locality, the Monteneve (Schneeberg) mine.

A reinvestigation of gabrielsonite from the holotype specimen from Långban, central Sweden, using single-crystal synchrotron X-ray diffraction, electron-microprobe techniques and Fourier-transform infrared (FTIR) spectroscopy, Raman and Mössbauer spectroscopies show that the mineral is an anhydrous Fe³⁺-bearing arsenite and not a hydrous Fe²⁺-bearing arsenate, as originally proposed. The revised ideal chemical formula of gabrielsonite is PbFe³(As³⁺O₃)O. The mineral is related to the descloizite supergroup, but it differs through the valencies of the non-Pb cations Fe (M³⁺ vs. M²⁺) and As (³⁺ vs. ⁴⁺) and through lower coordination of Pb (4 vs. 7–8) and As (3 vs. 4). The redefinition of gabrielsonite (proposal 17-G) has been approved by the Commission on New Minerals, Nomenclature and Classification (CNMNC) of the International Mineralogical Association.