Gorbunovite, CsLi2(Ti,Fe+3)(Si4O10)(F,OH,O)2, a new caesium trioctahedral mica, was discovered in the Darai-Pioz alkaline massif, Tajikistan. The mineral is named after the Russian chemist, leader of the Tajik-Pamir Expedition, Academician Nikolai Petrovich Gorbunov (1892–1938). Gorbunovite occurs as lamellar grains or flakes from 2 μm to 0.2 mm in a quartz–pectolite aggregate and is associated with quartz, fluorite, pectolite, baratovite, aegirine, leucosphenite, neptunite, reedmergnerite, orlovite, sokolovaite, mendeleevite-(Ce), odigitriaite, pekovite, zeravshanite, kirchhoffite and garmite. The mineral is colourless, transparent, with vitreous lustre. Mohs hardness is 2½. Dmeas. is 3.28 (2), Dcalc is 3.302 g/cm3. Gorbunovite is optically biaxial (–), α = 1.609(2), β = 1.621(2), γ = 1.623(2), 2Vmeas. 30(5) and 2Vcalc. 44. Gorbunovite is monoclinic, space group C2/m, C2 or Cm (polytype 1M), a = 5.236(2), b = 9.054(4), c = 10.767(4) Å, β = 99.61(4)°, V = 503.3(6) Å3 and Z = 2. The strongest lines in the powder X-ray diffraction pattern [d, Å, (I)] are: 4.49 (25), 3.94 (20), 3.69 (46), 3.57 (23), 3.45(34), 2.991 (42), 2.608 (77), 2.581 (100), 2.240 (33), 2.188 (62), 2.020 (24), 1.722 (27) and 1.511 (23). Chemical composition (microprobe analysis; H2O, Li2O – SIMS) is: SiO2 47.44, TiO2 9.40, Al2O3 0.66, MgO 0.63, Fe2O3 3.64, ZnO 1.01, K2O 0.39, Cs2O 26.64, Li2O 5.83, H2O 0.89, F 4.48, –O=F 1.89, total 99.17. The empirical formula is (Cs0.96K0.04)Σ1.00Li1.98(Ti0.60Fe+30.23Mg0.08Al0.07Zn0.06)Σ1.04Si4.00O10(F1.19OH0.50O0.31)Σ2.

Two uranyl carbonate silicate minerals have been studied in detail, lepersonnite-(Gd) and the new mineral lepersonnite-(Nd). Both minerals originate from Katanga province in the Democratic Republic of Congo (Africa): lepersonnite-(Gd) from the Shinkolobwe mine (type locality) and lepersonnite-(Nd) from the Swambo mine (type locality) and Shinkolobwe mine. Each occurs as radial to acicular aggregates composed of long prismatic, thin crystals, as the products of hydration–oxidation weathering of uraninite. A detailed description of the chemical and physical properties of lepersonnite-(Nd) is provided, including the thermal analysis of the -(Gd) member. Moreover, Raman and infrared spectroscopy data are provided for both minerals. The crystal structure of lepersonnite-(Gd) has been solved based on 3D electron diffraction data. According to the best dataset at 95 K, lepersonnite-(Gd) is orthorhombic, with a = 11.838(134) Å, b = 15.822(333) Å, c = 39.147(190) Å and V = 7353(282) Å3 (Z = 4). The dynamic refinement of the crystal structure (Robs/wRobs = 0.1204/0.1088 and Rall/wRall = 0.1204/0.1088 for 3090/50507 observed/all reflections and 247 refined parameters) revealed a large complex sheet structure with structural units defining a new lepersonnite topology. It contains infinite sheets of uranyl polyhedra, planar CO3 groups, protonated Si-tetrahedra, and Gd3+ polyhedra, and a thick interlayer hosted with H2O and partially occupied Ca2+ sites. Based on the structure refinement, bond-valence considerations, and new electron microprobe data, we infer that the ideal formula of lepersonnite-(Gd) is [Ca0.5Gd0.5(H2O)18(OH)1.5] [Gd(UO2)12(SiO3OH)2(CO3)4(OH)10O2(H2O)5]. On the basis of their closely related powder X-ray diffraction patterns and the similar behaviour of Nd and Gd, we expect the two minerals to adopt the same structures, apart from Ca, which was absent in lepersonnite-(Nd). The ideal formula for lepersonnite-(Nd) is [Nd(H2O)18(OH)2][Nd(UO2)12(SiO3OH)2(CO3)4(OH)10O2(H2O)5].

The new mineral natromolybdite, ideally Na2MoO4·2H2O, was found in the Arsenatnaya fumarole, Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. The associated minerals are halite, sylvite, aphthitalite, belomarinaite, powellite, hematite, sanidine, tilasite, johillerite, bradaczekite, badalovite, arsmirandite, wrightite, arsenatrotitanite, dmisokolovite, litidionite, rutile and cristobalite. Natromolybdite occurs as rectangular, octagonal or rhomb-like lamellar to thin-tabular crystals up to 40 μm across and up to 3 μm thick, in near-parallel, pile-like or rose-like aggregates and crystal crusts up to 0.2 mm across. It is transparent and colourless, with vitreous lustre. Dcalc is 2.573 g/cm3. The synthetic analogue of natromolybdite is optically biaxial (+), α = 1.575(2), β = 1.576(2), γ = 1.598(3) and 2Vmeas = 20(10)°. The chemical composition (wt.%, electron microprobe, H2O is calculated by stoichiometry) is: Na2O 25.51, K2O 0.66, SO3 1.04, MoO3 58.21, H2Ocalc 15.05, total 100.47. The empirical formula, calculated based on O = 6 apfu, is (Na1.971K0.034)Σ2.005(Mo0.968S0.031)Σ0.999O4·2H2O. Natromolybdite is orthorhombic, space group Pbca, a = 8.483(1), b = 10.577(2), c = 13.842(2) Å, V = 1242.0(2) Å3 and Z = 8. The nine strongest reflections of the powder XRD pattern [d,Å(I)(hkl)] are: 6.92(100)(002), 4.243(20)(200), 4.206(32)(022), 3.618(31)(202), 3.310(31)(220), 3.169(49)(131), 3.067(21)(114), 2.987(30)(222) and 2.681(15)(204, 311). Natromolybdite (IMA-accepted symbol Nmyb) is named for the chemical composition. It is a natural analogue of a well-studied synthetic sodium molybdate dihydrate.

Phosphide-bearing diopside–anorthite paralava found in the distribution area of the pyrometamorphic rocks of the Hatrurim Complex in Jordan (Daba-Siwaqa field) and Israel (Hatrurim Basin field) have yielded a large number of new phosphides and phosphates. In 2019, a small outcrop of phosphide-bearing breccia with cement composed of gehlenite–flamite paralava was discovered in the Hatrurim Basin. A new pyrophosphate, yamhamelachite, KCrP2O7 (P21/c, a = 7.3574(3), b = 9.9336(4), c = 8.1540(4) Å, β = 106.712(5)°, V = 570.77(5) Å3 and Z = 4), occurs at the phosphide-enriched boundary between an altered sedimentary xenolith and the gehlenite–flamite paralava. Yamhamelachite forms green aggregates in which the size of grains does not exceed 25–30 μm. The mineral is transparent with a glassy lustre. Yamhamelachite is brittle with conchoidal fracture. Mohs hardness = 4. The empirical formula of yamhamelachite calculated on the basis of average microprobe analyses is (K0.89Ca0.01□0.10)Σ1.00 Cr3+0.50V3+0.33Al0.15Fe3+0.04 Ti4+0.03)Σ1.05P1.98O7. The density calculated from the empirical formula and structural data is 3.035 g·cm–3. Cr3+ in yamhamelachite is substituted by V3+, and in a few cases V is marginally more abundant than Cr, indicating the presence of a potentially new mineral with the formula KVP2O7. Yamhamelachite consists of layers of Cr3+-octahedra and pyrophosphate groups connected at their apices, and potassium located within channels parallel to [001]. A characteristic feature of phosphide aggregates associated with yamhamelachite is the presence of two generations of barringerite, the earlier of which has higher Cr and V content. In the general crystallisation sequence, yamhamelachite appears after phosphides (+pyrrhotite and daubréelite) and then spinels of the chromite–magnetite series crystallise, along with ferromerrillite and ferroalluaudite. The source of chromium for yamhamelachite was mainly V–Cr-bearing pyrrhotite and V-bearing daubréelite. The low Fe3+ content in yamhamelachite, probably related to its late-stage alteration, indicates that it crystallised from phosphate melt under reducing conditions at ∼1000°С.

The new ixiolite-group mineral nioboixiolite-(Fe3+), ideally (Nb0.5Fe3+0.5)O2, was discovered in nosean sanidinite of the Laach Lake (Laacher See) volcano, Eifel region, Rhineland-Palatinate, Germany. The associated minerals are sanidine, K-bearing albite, nosean, biotite, Nb-rich ilmenite, Ti-rich magnetite, hercynite, corundum, samarskite-(Y), ekebergite and columbite-(Fe). Nioboixiolite-(Fe3+) forms long prismatic to acicular crystals up to 0.03 × 0.06 × 1 mm and epitaxial intergrowths with ilmenite and intermediate members of the samarskite–ekebergite series. Both colour and streak are black and the lustre is submetallic. The new mineral is brittle, with the Vickers’ micro-indentation hardness of 499 kg mm–2 which corresponds to the Mohs’ hardness of 5. No cleavage is observed. The fracture is conchoidal. The calculated density is 5.033 g·cm–3. In reflected light, nioboixiolite-(Fe3+) is grey, no pleochroism is observed. The reflectance values (Rmin, %/Rmax, %/λ, nm) are: 14.7/16.4/470, 14.3/15.9/546, 14.1/15.7/589 and 14.0/15.8/650. The Raman spectrum shows bands corresponding to stretching vibrations of (Nb,Ti)–O–(Nb,Ti) and (Nb,Ti)–O–Mn2+ and the absence of bands of OH groups. The chemical composition is (electron microprobe data, wt.%): MgO 0.41, MnO 3.52, Al2O3 0.42, Cr2O3 0.75, Fe2O3 20.23, TiO2 22.26, ZrO2 0.76, Nb2O5 51.82, total 100.17. The empirical formula is (Mg0.04Mn2+0.20)Σ0.24(Al0.03Cr0.04Fe3+1.01)Σ1.08(Ti1.11Zr0.02)Σ1.13Nb1.55O8 (Z = 1). The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 3.586 (29) (110), 2.917 (100) (111), 2.503 (18) (002), 2.170 (18) (121), 1.738 (22) (130), 1.689 (26) (221). The crystal structure was determined using single-crystal X-ray diffraction data and refined to R = 0.0447. Nioboixiolite-(Fe3+) is orthorhombic with space group Pbcn, a = 4.6578(6), b = 5.6230(7), c = 5.0182(5) Å and V = 131.43(3) Å3. The new mineral is isostructural with other members of the ixiolite group.

Nancyrossite, ideally FeGeO6H5, is a new hydroxyperovskite from Tsumeb. It probably formed by the oxidation and partial dehydrogenation of stottite, FeGe(OH)6, with which it is associated intimately. The structure of nancyrossite has been determined in tetragonal space group P42/n: a = 7.37382(12) Å, c = 7.29704(19) Å, V = 396.764(16) Å3, Z = 4, R1(all) = 0.034, wR2(all) = 0.051 and GoF = 1.057. Empirical formulae of two crystals have almost end-member compositions, Fe3+1.01Zn0.03Ge0.98O6H5 and Fe3+1.01Zn0.04Ge0.98O6H5. Structure determination indicates that 88% of the Fe is ferric. The chemical formula proposed here for nancyrossite recognises that although H atoms form OH groups, writing the formula as FeGeO(OH)5 implies that one of the six oxygen atoms is very underbonded, with a bond-valence sum of only ∼1.2 valence units. As such, H in nancyrossite may have novel crystal chemistry. For example, the five H atoms may be distributed dynamically over the six O atoms, a phenomenon that would be averaged by X-ray diffraction, and so go undetected. Nancyrossite is the Ge-analogue of jeanbandyite. By analogy with nancyrossite, we propose revision of the ideal formula of jeanbandyite from FeSnO(OH)5 (Welch and Kampf, 2017) to FeSnO6H5.

The new mineral tarutinoite, ideally Ag3Pb7Bi7S19, was found in a fragment of a drill core extracted at the 178.5 m level of borehole #4604 at the Tarutinskoe (Tarutino) copper-skarn deposit, Chelyabinsk Oblast, Southern Urals, Russia. It occurs as anhedral grains up to 0.10 × 0.05 mm intergrown with hessite and galena in magnetite and calcite. Tarutinoite is grey, opaque with metallic lustre, brittle tenacity and uneven fracture. No cleavage and parting are observed. The Vickers’ micro-indentation hardness (VHN, 25 g load) is 178 kg/mm2 (range 165–194, n = 4), corresponding to a Mohs’ hardness of 3.5–4, and calculated density is 7.180 g/cm3. In reflected light, tarutinoite is greyish-white, very weakly bireflectant and non-pleochroic. Under crossed polarisers the new mineral exhibits moderate anisotropy, in grey and dark grey tones with bluish tints. The reflectance values for wavelengths recommended by the Commission on Ore Mineralogy of the International Mineralogical Association are (Rmin/Rmax, %): 45.5/47.9 (470 nm), 43.5/45.0 (546 nm), 43.3/44.1 (589 nm) and 41.8/42.5 (650 nm). The chemical composition (wt.%, electron microprobe data, mean of 7 spot analyses) is Cu 0.30, Ag 8.33, Cd 0.04, Pb 37.12, Bi 37.52, S 15.15, Se 0.40, Te 0.66, total 99.52. The empirical formula calculated on the basis of 36 atoms per formula unit is (Ag3.01Cu0.18)Σ3.19(Pb6.98Cd0.01)Σ6.99Bi7.00(S18.42Se0.20Te0.20)Σ18.82. Tarutinoite is monoclinic, space group C2/m, with a = 13.5447(12), b = 4.1027(3), c = 32.481(4) Å, β = 96.433(9)°, V = 1793.6(3) Å3 and Z = 2. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 16.15 (48) (0 0 2), 3.407 (69) (1 1 –5), 3.328 (95) (2 0 –9), 3.042 (65) (2 0 –10), 2.941 (100) (3 1 2), 2.910 (55) (3 1 –4), 2.053 (44) (0 2 0). The crystal structure of tarutinoite was refined to R1 = 0.1349 for 2024 reflections with Fo > 4σ(Fo) and 84 refined parameters. The new mineral is the first 7,8L member of the lillianite homologous series. It is named after its type locality.

Anorthoyttrialite-(Y) occurs as inclusions in yttrian fluorite from the Stetind pegmatite, Narvik, Nordland, Norway, associated with allanite-(Ce), alnaperbøeite-(Ce), bastnäsite-(Ce), fluorite, hematite, hundholmenite-(Y), perbøeite-(Ce), rowlandite-(Y), schlüterite-(Y), synchysite-(Y), thalénite-(Y), törnebohmite-(Ce) and vyuntspakhkite-(Y). It forms translucent tabular or needle shaped crystals, which are colourless or white, yellow or brownish. It is optically biaxial (–) with α = 1.705(1), β = 1.750(1), γ = 1.756(2) and 2Vcalc = 39.09°. The calculated and measured density is 5.24 g·cm–3 and 5.1 g·cm–3 respectively. The empirical formula of anorthoyttrialite-(Y) based on 14 oxygen atoms per formula unit is (Y1.561La0.033Ce0.242Pr0.059Nd0.367Sm0.177Gd0.298Tb0.036Dy0.297Ho0.058Er0.258Tm0.071Yb0.385Lu0.041Ca0.099Mn0.029U0.003Th0.01)Σ4.024Si4.011O14.

Two polytypic crystal structures have been determined in triclinic space group $P\bar 1$. Anorthoyttrialite-(Y)-1A is isostructural with the B-type structure known for synthetic rare earth element disilicates of composition REE2Si2O7, where REE = Y, Eu, Gd, Tb, Dy, Ho, Er, Tm. Unit cell parameters are a = 6.6107(4), b = 6.7139(3), c = 12.2034(9) Å, α = 94.819(3), β = 90.583(3), γ = 91.742(3)° and V = 539.42(5) Å3 with Z = 2. The five strongest lines in the calculated powder diffraction pattern are (d in Å (I) hkl) as follows: 4.369 (72) $1\bar 1\bar 1$, 3.040 (100) 004, 3.040 (71) $02\bar 2$, 2.918 (68) $\bar 202$, 2.814 (59) 211. Anorthoyttrialite-(Y)-2A has unit cell parameters a = 6.6068(6), b = 6.7147(6), c = 24.218(2) Å, α = 94.435(6), β = 90.315(5), γ = 92.092(5)°, V = 1070.41(16) Å3 and Z = 4. The five strongest lines in the calculated powder diffraction pattern are: 4.378 (75) $1\bar 1\bar 2$, 3.027 (79) $0\bar 24$, 3.018 (100) 008, 2.907 (68) $\bar 204$, 2.810 (59) 212. Both polytypes contain linear trisilicate anion groups [Si3O10]8– as well as isolated [SiO4]4– tetrahedra, while the REE are six-, eight-, and nine-coordinated by oxygen. The crystal structures consist of essentially two types of layers with different stacking order. Similar layer stacking is discussed in relation to other rare earth disilicates like percleveite-(Ce) and thortveitite. Anorthoyttrialite-(Y) is also compared to a heat treated metamict Y-silicate from Stetind.

The sulfide-free metasomatic rocks with chalcophile metals from the Nežilovo ore field, near Veles, Republic of North Macedonia belong to a rare kind of ore. The mineralogy and petrology of these rocks were studied in detail and can be considered as a standard description for ores of this type. A characteristic feature of Nežilovo-type ores is a wide variety of accessory oxide minerals containing chalcophile elements (Zn, Pb, Sb, Cu and As). The new nolanite-supergroup mineral zincorinmanite-(Zn), ideally (Fe3+2Zn)SbZnO7(OH), was discovered in the Nežilovo ore. The associated minerals are quartz, baryte, gahnite, Zn-bearing phlogopite, together with accessory hematite, almeidaite, a Pb-analogue of hydroxycalcioroméite and an insufficiently studied Sb-rich högbomite-supergroup mineral. Zincorinmanite-(Zn) forms lamellar to tabular subhedral single-crystal grains up to 0.5 mm across and up to 40 μm thick. The colour and streak are black and the lustre is submetallic. The new mineral is brittle, with the Mohs’ hardness of 6. No cleavage is observed. The fracture is uneven. The calculated density is 5.446 g·cm–3. In reflected light, zincorinmanite-(Zn) is light grey, no pleochroism is observed. The reflectance values (Rmin, %/Rmax, %/λ, nm) are: 12.6/13.7/470, 12.1/13.2/546, 11.8/12.8/589 and 11.5/12.2/650. The Raman spectrum shows bands corresponding to the O–H and Sb–O stretching vibrations and (Fe3+,M2+)–O–H bending modes. The chemical composition is (electron microprobe data, with iron divided into Fe2O3 and FeO based on the charge balance and H2O calculated from the structural data, wt.%): MgO 1.42, MnO 0.44, FeO 2.04, ZnO 22.55, Al2O3 1.95, Fe2O3 35.59, TiO2 1.51, Sb2O5 33.05, H2O 1.18, total 99.73. The empirical formula is [(Fe3+2.12Al0.18)(Zn0.32Mg0.16Fe2+0.13Mn0.03)Ti0.06]Σ3.00(Sb0.97Ti0.03)Σ1.00Zn1.00O7[(OH)0.61O0.39]Σ1.00. The crystal structure was determined using single-crystal X-ray diffraction data and refined to R = 0.0191. Zincorinmanite-(Zn) is hexagonal, space group P63mc, a = 5.9720(1), c = 9.3578(1) Å and V = 289.031(8) Å3 (Z = 2). The new mineral is isostructural with other members of the nolanite group. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) – hkl] are: 5.176 (46) – 100; 3.473 (77) – 102; 2.989 (46) – 110; 2.674 (86) – 103; 2.520 (100) – 112; and 2.496 (42) – 201.

The new mineral manganonewberyite (IMA2024–004), Mn(PO3OH)(H2O)3, was found underground at the Cassagna mine, Liguria, Italy, where it is a secondary phase formed by the interaction of bat guano with Mn-rich rock. Manganonewberyite occurs with niahite, kutnohorite, sampleite and serrabrancaite on a tinzenite–quartz–braunite matrix. Crystals are prisms and blades, up to ∼0.15 mm long, elongated parallel to [001], flattened on {100} and exhibiting the forms {100}, {010} and {111}. Crystals are colourless and transparent, with vitreous lustre and white streak. The mineral is brittle with curved fracture. The Mohs hardness is ∼3. Cleavage is perfect on {010}. The density is 2.34(2) g·cm–3. Optically, manganonewberyite is biaxial (+) with α = 1.541(2), β = 1.547(2) and γ = 1.559(2) (white light). The 2V is 71.6(3)°. The optical orientation is X = a, Y = b and Z = c. The empirical formula is (Mn0.960Mg0.016Ca0.015)Σ0.991(H1.02P1.00O4)(H2O)3. Manganonewberyite is orthorhombic, space group Pbca, with cell parameters: a = 10.4273(6), b = 10.8755(8), c = 10.2126(4) Å, V = 1158.13(11) Å3 and Z = 8. The crystal structure (R1 = 2.79% for 892 I > 2σI reflections) is the same as that of newberyite with Mn in place of Mg.

Marsaalamite-(Y), ideally Y(MoO4)OH, is a new molybdate mineral discovered in the greisenised Um Safi F-rich granite located in the Marsa Alam District, Central Eastern Desert, Egypt. It typically occurs as inclusions in or intergrowths with F-rich zinnwaldite. It forms micaceous aggregates, with sizes varying from 0.1 to 1 mm. Marsaalamite-(Y) is non-magnetic, white in colour, and has an earthy lustre and white streak. It is brittle (3–4 Mohs) and has basal cleavages {010}. The calculated density is 4.90 g.cm–3 based on the empirical formula and unit-cell parameters refined from powder X-ray diffraction data. Marsaalamite-(Y) is associated with arsenopyrite, baryte, bastnäsite-(Ce), cassiterite, chernovite-(Y), columbite-(Fe), fluocerite-(Ce), fluorite, iron oxy-hydroxides, löllingite, molybdenite, monazite-(Ce), pyrite, quartz, rutile, thorite, wolframite, wulfenite, xenotime-(Y) and several unidentified phases. The empirical formula is (Y0.67Er0.10Dy0.08Yb0.08Ho0.02Lu0.02Tm0.02Ca0.01)Σ1.00(Mo0.95S0.03As0.01P0.01)Σ1.00O4.00[(OH)0.88F0.11Cl0.01]Σ1.00; the ideal end-member formula is Y(MoO4)(OH). The presence of a hydroxyl group has been confirmed by Raman and infrared spectroscopy, and its concentration has been calculated from the stoichiometry. Marsaalamite-(Y) is the natural (OH)-dominant analogue of synthetic Y(MoO4)F. It is monoclinic, space group P21/c, with unit-cell parameters a = 5.1863(7) Å, b = 12.3203(11) Å, c = 6.6953(7) Å, β = 114.173(8)°, V = 390.30(8) Å3, and Z = 4. Extreme fractionation of the parental halogen-rich, A-type granitic magma triggered the greisenisation of the granite. Marsaalamite-(Y) occurred simultaneously with or immediately after the crystallisation of F-rich zinnwaldite based on the textural relationship. Therefore, the crystallisation of marsaalamite-(Y) was most likely to have been controlled by fluid-induced processes rather than magmatic conditions. The new mineral has been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA 2024-050) and named after the Marsa Alam District, Al-Bahr Al-Ahmer Governorate, Egypt.

Parisite-(Nd) (IMA2024-013), ideally CaNd2(CO3)3F2, as the Nd-dominant analogue of parisite-(Ce), occurs in dolomitic marble in the Bayan Obo Fe–Nb–REE deposit, Inner Mongolia, China. It is associated with calcite, aegirine, magnetite, hematite, fluorite, riebeckite, bastnäsite-(Ce), baryte, aeschynite-(Ce), aeschynite-(Nd), monazite and parisite-(Ce). Parisite-(Nd) occurs as subhedral to anhedral irregular grains from 0.02 mm to 1 mm. Parisite-(Nd) is transparent, yellowish-brown colour, with pale yellow streak and displays vitreous to resinous lustre. Cleavage is distinct on pseudo-{001}; fracture is uneven, or conchoidal. The Mohs hardness is 4 to 5, and it is brittle. The calculated density of parisite-(Nd) is 4.357 g/cm3. Parisite-(Nd) is pseudo-uniaxial (+), ω = (1.679) and ε = (1.754). The empirical formula is (Ca0.945Fe0.058Sr0.015Ba0.007)Σ1.025(Nd0.967Ce0.529La0.191Pr0.137Gd0.070Sm0.029Th0.022Y0.016Nb0.011Ho0.003)Σ1.975(CO3)3F1.893OH0.023. The Raman spectra of parisite-(Nd) show strong and sharp peaks at 1113, 1090, 825, 635 and 1608 cm–1 and moderate to weak bands centred at 255, 392, 739, 924, 1183, 1228, 1296, 1640, 2247, 2924 and 3065 cm–1. Powder X-ray diffraction and TEM studies give the following results: monoclinic, space group: Cc (# 9), a = 12.3283(13) Å, b = 7.1185(4) Å, c = 28.4633(37) Å, β = 98.529(14)°, V = 2470.28(42) Å3 and Z = 12.

Xenotime-(Gd), ideally GdPO4, is a new mineral of the xenotime group. It was discovered at the Zimná Voda REE–U–Au occurrence near Prakovce, Western Carpathians, Slovakia. It forms rare crystal domains (≤20 μm, usually ≤10 μm in size) in Gd-rich xenotime-(Y) crystals (≤100 μm in size), in association with monazite-group minerals, uraninite, fluorapatite and uranyl arsenates–phosphates. The hydrothermal REE–U–Au mineralisation occurs in a quartz–muscovite vein, hosted in Palaeozoic phyllites near exocontact with Permian granites. The density is 5.26 g/cm3, based on calculated average empirical formula and unit-cell parameters. The average chemical composition (n = 6) measured by electron microprobe is as follows (wt.%): P2O5 30.1, As2O5 0.5, SiO2 0.2, UO2 0.3, Y2O3 15.7, (La, Ce, Pr, Nd)2O3 0.5, Sm2O3 5.7, Eu2O3 1.4, Gd2O3 29.2, Tb2O3 3.9, Dy2O3 10.4, Ho2O3 0.4, (Er, Tm, Yb, Lu)2O3 2.1, (Ca, Fe, Pb, Mn, Ba)O 0.1, total 100.5. The corresponding empirical formula calculated on the basis of 4 oxygen atoms is: (Gd0.37Y0.32Dy0.13Sm0.08Tb0.05Eu0.02Er0.01Tm0.01Nd0.01…)Σ1.01(P0.98As0.01Si0.01)O4. The empirical formula of the Gd-richest composition is: (Gd0.38Y0.31Dy0.13Sm0.08Tb0.05Eu0.02Er0.01Nd0.01Ho0.01…)Σ1.01(P0.98As0.01Si0.01)O4. The ideal formula is GdPO4. The xenotime-type structure has been confirmed by micro-Raman spectroscopy and a Fast Fourier-Transform pattern using HRTEM. Xenotime-(Gd) is tetragonal, space group I41/amd, a = 6.9589(5) Å, c = 6.0518(6) Å, V = 293.07(3) Å3 and Z = 4. The new mineral is named as an analogue of xenotime-(Y) and xenotime-(Yb) with Gd dominant among the REE. The middle REE enrichment of xenotime-(Gd) is shared with the associated monazite-(Gd) and Gd-rich hingganite-(Y). This exotic REE signature and precipitation of Gd-bearing minerals is a product of selective complexing and enrichment in MREE in low-temperature hydrothermal fluids by alteration of uraninite, brannerite and fluorapatite on a micro-scale. The existence of xenotime-(Gd) and monazite-(Gd) is the first naturally documented dimorphism among REE phosphates. In addition, xenotime-(Gd) is only the third approved Gd-dominant mineral, after lepersonnite-(Gd) and monazite-(Gd).

Rundqvistite-(Ce), ideally Na3(Sr3Ce)(Zn2Si8O24), is a new mineral from the Darai-Pioz alkaline massif, Tien-Shan Mountains, Tajikistan. The mineral occurs as elongated grains up to 0.1 mm long and up to 0.03 mm thick embedded in quartz–pectolite aggregate in a silexite-like peralkaline pegmatite. Associated minerals are quartz, fluorite, pectolite, baratovite, aegirine, leucosphenite, neptunite, reedmergnerite, orlovite, sokolovaite, mendeleevite-(Ce), odigitriaite, pekovite, zeravshanite, kirchhoffite and garmite. The mineral is colourless with a vitreous lustre and a white streak, brittle, Dmeas. is 3.70(2) and Dcalc. is 3.709 g/cm3. Rundqvistite-(Ce) is monoclinic, space group P21/c, a = 5.1934(16), b = 7.8934(16), c = 26.011(5) Å, β = 90.02(3)° and V = 1066.3(4) Å3. The chemical composition of rundqvistite-(Ce) is SiO2 40.17, La2O3 2.64, Ce2O3 7.55, Pr2O3 0.80, Nd2O3 2.43, Sm2O3 0.33, Eu2O3 0.09, Gd2O3 0.24, Tb2O3 0.18, Dy2O3 0.21, PbO 1.03, SrO 19.83, FeO 0.37, ZnO 13.08, CaO 2.55, Na2O 8.04, total 99.54 wt.%. The empirical formula calculated on 24 O apfu (atoms per formula unit) is Na3.10Sr2.29Ca0.54Pb0.06(Ce0.55La0.19Nd0.17Pr0.06Sm0.02Gd0.02Eu0.01Tb0.01Dy0.01)Σ1.04Zn1.92Fe0.06 Si8.00O24 Z = 2. The structural formula based on refined site-occupancies is (Na2.94Sr0.06)Σ3.00 [(Sr2.23Ca0.54Pb0.06Na0.13)Σ2.96Ln3+1.04]Σ4.00[(Zn1.92Fe2+0.06)Σ1.98Si8O24], where Ln3+1.04 = (Ce0.55La0.19Nd0.17Pr0.06Sm0.02Gd0.02Eu0.01Tb0.01Dy0.01)Σ1.04. The crystal structure of rundqvistite-(Ce) was refined to R1 = 2.76% on the basis of 3184 unique reflections [F > 4σ|F|]. In rundqvistite-(Ce), the main structural unit is a (Zn2Si8O24)12– sheet parallel to (100). In the sheet, the Si and Zn tetrahedra form four-, five- and eight-membered rings. The interstitial cations at the Na and M(1–3) sites sum to [Na3(Sr3Ce)]12– apfu. The Na and M(1–3) polyhedra share common edges to form a layer. Rundqvistite-(Ce) is a structural analogue of vladykinite, ideally Na3Sr4(Fe2+Fe3+)Si8O24. Rundqvistite-(Ce) and vladykinite are related by the following substitution: [8]Ce3+ + [4](Zn2+)2 ↔ [8]Sr2+ + [4](Fe2+Fe3+). The mineral is named after Dmitry Vasilievich Rundqvist (1930–2022), a prominent Russian geologist and an expert on the geology of ore deposits, metallogeny and mineralogy of Precambrian rocks.

Hydroxylbastnäsite-(La), the OH- and La-dominant member of the bastnäsite group, in fact known for many years, was studied in detail and has been approved by the IMA–CNMNC as a new mineral species with the ideal, end-member formula La(CO3)(OH). The holotype originates from the Vuoriyarvi (another spelling: Vuorijärvi) alkaline-ultrabasic complex, Northern Karelia, and the cotype from the Mochalin Log REE deposit, Potaniny Mts, South Urals, both in Russia. At Vuoriyarvi, hydroxylbastnäsite-(La) occurs as clusters (up to 1 mm) of light brown, honey-yellow or colourless hexagonal tabular to short-prismatic crystals up to 0.15 mm associated with fluorite and ancylite-(Ce) in cavities of calcite–dolomite carbonatites. At Mochalin Log, hydroxylbastnäsite-(La) forms light brown grains up to 0.2 mm included in massive aggregates of other LREE minerals: bastnäsite-(Ce), bastnäsite-(La), percleveite-(Ce), percleveite-(La), biraite-(Ce), biraite-(La), törnebohmite-(La), ferriperbøeite-(Ce), allanite-(Ce), etc. Dmeas is 4.75(2) and Dcalc is 4.778 g cm–3 (holotype). Hydroxylbastnäsite-(La) is optically uniaxial (+), ω = 1.76(1) and ε = 1.86(1) (holotype). The chemical composition (wt.%, electron microprobe, CO2 and H2O calculated: holotype/cotype) is: CaO 0.23/0.00, SrO 0.07/0.00, La2O3 39.47/39.58, Ce2O3 33.51/31.99, Pr2O3 1.03/1.51, Nd2O3 1.95/2.38, F 0.76/3.33, CO2 20.49/20.34, H2O 3.77/2.58, –O=F 0.32/1.40, total 100.96/100.31. The empirical formulae, calculated based on the sum of metal cations of 1 apfu and one CO3 group pfu, are (La0.52Ce0.44Nd0.02Pr0.01Ca0.01)Σ1.00(CO3)[(OH)0.90F0.09]Σ0.99 (holotype) and (La0.53Ce0.42Nd0.03Pr0.02)Σ1.00(CO3)[(OH)0.62F0.38]Σ1.00 (cotype). Hydroxylbastnäsite-(La) is hexagonal, P6̅, unit-cell parameters (from powder XRD data, holotype/cotype) are: a = 12.537(3)/12.533(1), c = 9.968(2)/9.908(1) Å, V = 1356.8(5)/1347.9(3) Å3 and Z = 18. Strong reflections of the powder XRD pattern [d,Å(I)(hkl)] are (holotype): 4.98(39)(002), 3.616(88)(300), 2.926(100)(302), 2.089(41)(330), 2.052(46)(304) and 1.927(40)(332). The crystal structure of holotype hydroxylbastnäsite-(La) was refined by the Rietveld method, Rwp = 0.0071, Rp = 0.0050, Robs = 0.0466. It is isostructural to hydroxylbastnäsite-(Ce) and synthetic bastnäsite-type hydroxyl-carbonates REE3+(CO3)(OH) (REE = La–Er), but differs from fluorine-dominant bastnäsites which adopt the space group P6̅2c.

The new mineral zincostottite (IMA2024-024), ZnGe(OH)6, was found on specimens from the Tsumeb mine, Tsumeb, Namibia, where it is a secondary oxidation-zone mineral. It occurs as heavily etched remnants of equant or tabular crystals, up to ∼1 mm in diameter. Crystals are colourless and transparent, with vitreous to subadamantine lustre and a white streak. The mineral is brittle with irregular stepped fracture. The Mohs hardness is ∼4.5. Cleavage is good on {100} and poor on {001}. The calculated density is 3.834 g·cm–3. Optically, zincostottite is uniaxial (–) with ω = 1.785(5) and ε = 1.765(5) (white light). The empirical formula is (Zn0.77Fe3+0.23)Σ1.00Ge1.00O6H5.77. Zincostottite is tetragonal, space group P42/n, with cell parameters: a = 7.4522(18), c = 7.4000(8) Å, V = 411.0(2) Å3 and Z = 4. The crystal structure (R1 = 2.65% for 452 I > 2σI reflections) is the same as that of stottite with Zn in place of Fe2+

Ferrodimolybdenite with ideal formula FeMo3+2S4 (C2/c, a = 11.8249(8) Å, b = 6.5534(3) Å, c = 13.0052(10) Å, β = 114.474(9)°, V = 917.27(12) Å3 and Z = 8) was discovered in a differentiated sulfide nodule composed of troilite and pentlandite parts. The nodule was detected in the central zone of a diopside–anorthite–tridymite oval paralava body, ∼30 metres in diameter, within the pyrometamorphic Hatrurim Complex in Daba-Siwaqa, Jordan. Ferrodimolybdenite is the first trivalent molybdenum compound discovered in Nature. Its synthetic analogue crystallises in the C1c1 space group. Ferrodimolybdenite with the empirical formula (Fe2+0.99Cu2+0.07Ni2+0.04)Σ1.10Mo3+1.94(S2–3.98P3–0.02)Σ4.00 was identified in the troilite part of the differentiated sulfide nodule. The nodule contains inclusions of tetrataenite, nickelphosphide, molybdenite, galena and rudashevskyite. Ferrodimolybdenite forms platy crystals with dimensions ranging from 3×100 μm to 20×40 μm. The mineral exhibits a grey colour and a dark grey streak. It is opaque with a metallic lustre, and its Mohs hardness is ∼3. The cleavage observed in the mineral is perfect on {001}, good on {100} and poor on {010}. Its tenacity is sectile, and its fracture is smooth. The calculated density of 5.445 g·cm–3 was derived from the empirical formula and unit cell volume refined from single-crystal X-ray diffraction data. In reflected light, ferrodimolybdenite appears grey to light grey with a blueish tinge. It is anisotropic, with a reflectance in the range of 34–40%. The crystallisation of ferrodimolybdenite occurred in reduced conditions in monosulfide Fe(+Ni) melt at a temperature of 1000–1100°C and at low pressure.