Kozłowskiite, ideally Ca4(Fe2+Sn3)(Si2O7)2(Si2O6OH)2, is a new mineral isostructural with kristiansenite and silesiaite, found as a band in the core of a zoned silesiaite–kristiansenite crystal from the granitic pegmatite at Szklarska Poręba, Lower Silesia, Poland. In tiny pieces kozłowskiite is pale brownish, with a calculated density of 3.775 g⋅cm–3 and a mean refractive index ~1.727. The triclinic crystal structure was determined with space-group symmetry C1: a = 10.0183(2), b = 8.3861(1), c = 13.3395(2) Å, α = 89.956(1), β = 109.039(2), γ = 89.979(1)° and V = 1059.40(3) Å3, although, similarly to kristiansenite, it is metrically monoclinic (Laue group 2/m) with α and γ angles equal to 90° and a = 10.0170(3), b = 8.3860(2), c = 13.3421(4) Å, β = 109.050(3)° and V = 1059.40(5) Å3. The seven strongest reflections in the calculated powder X-ray diffraction pattern are [d in Å (I) hkl]: 5.190 (73.2) 111, 1$\bar{1}$1; 4.569 (30.0) $\bar{2}$02; 3.153 (64.7) 004; 3.094 (28.1) $\bar{3}$11, $\bar{3}\bar{1}$1; 3.089 (100) $\bar{2}\bar{2}$2, $\bar{2}$22; 2.595 (27.2) 2$\bar{2}$2, 222; and 2.141 (30.6) $\bar{3}$31, $\bar{3}\bar{3}$1. Electron microprobe analysis gave (in wt.%) SiO2 39.46, ZrO2 0.35, SnO2 31.13, Al2O3 0.35, Sc2O3 2.65, total Fe as Fe2O3 5.06 (= Fe2O3calc. 2.26; FeOcalc. 2.52), MnO 0.71, CaO 18.42 and H2Ocalc. 1.48, sum 99.33. The empirical formula on the basis of 26O + 2(OH) and 16 cations (Z = 2) is Ca4.00(Sn2.52Sc0.47Fe2+0.43Fe3+0.34Mn2+0.12Al0.08Zr0.03)Σ4.00(Si2.00O7)2(Si2.00O6OH)2. The crystal structure of kozłowskiite was refined to an R1 = 2.12% for 4887 reflections with Io>2σI. The Ca and Si sites are occupied solely by Ca and Si, respectively, and three of four M sites: M2, M3 and M4, are dominated by Sn. Four hydrogen atoms present in the kozłowskiite unit cell are shared among the O17–O27 and O47–O37 oxygen atoms where O17 and O47 are OH groups forming relatively strong hydrogen bonds.

Garpenbergite is a new mineral (IMA2020-099) from the Garpenberg Norra mine, Hedemora, Dalarna, Sweden. It occurs with carlfrancisite and minor stibarsen, paradocrasite and filipstadite in a fractured skarn matrix of granular jacobsite, alleghanyite, kutnohorite and dolomite. Crystals are short-prismatic, up to 1.5 mm in length. They have a blackish to greyish brown colour, and are lustrous semi-opaque, with brown streak. Garpenbergite is brittle, with an uneven to subconchoidal fracture. Cleavage is distinct on {010}. Hardness ≈ 5 (Mohs) and VHN100 = 650(40). Dcalc = 4.47(1) g⋅cm−3, overall ncalc = 1.85. Maximum specular reflectance values (%) obtained are 9.2 (470 nm), 9.1 (546 nm), 9.0 (589 nm) and 8.9 (650 nm). The empirical chemical formula of garpenbergite, based on electron microprobe data, is (Mn2+3.97Mg1.48Mn3+0.26Zn0.29)Σ6.00(As0.89Fe3+0.04Mn3+0.06Si0.01)Σ1.00(Sb0.98Fe0.02)Σ1O10[(OH)1.99Cl0.01]Σ2.00. The five strongest Bragg peaks in the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are 3.05 (30) (002), 2.665 (100) (161), 2.616 (40) (301), 2.586 (25) (251) and 1.545 (45) (462). The orthorhombic unit-cell dimensions (in Å) are a = 8.6790(9), b = 18.9057(19) and c = 6.1066(6), with V = 1001.99(18) Å3 for Z = 4. The crystal structure was refined from single-crystal X-ray diffraction data in the space-group Ibmm to R1 = 3.7% for 957 reflections. Garpenbergite, ideally Mn6As5+Sb5+O10(OH)2, is isostructural with manganostibite, Mn7AsSbO12, but possesses a cation vacancy (□) at an octahedrally coordinated structural site; the two minerals are thus related by the exchange Mn2+ + 2O2– → □ + 2(OH)–. The presence of hydroxyl groups is supported by vibration bands at 3647 and 3622 cm−1 in the Raman spectrum of garpenbergite and by bond-valence considerations.

The new mineral percleveite-(La) (IMA2019–037), ideally La2Si2O7, was found in polymineralic nodules of the Mochalin Log REE deposit, Chelyabinsk Oblast, South Urals, Russia. It is associated with allanite-(Ce), allanite-(La), bastnäsite-(Ce), bastnäsite-(La), ferriallanite-(Ce), ferriallanite-(La), ferriperbøeite-(Ce), ferriperbøeite-(La), fluorbritholite-(Ce), hydroxylbastnäsite-(Ce), perbøeite-(Ce), perbøeite-(La), törnebohmite-(Ce) and törnebohmite-(La). Percleveite-(La) occurs as isolated anhedral grains commonly up to 0.2 mm × 0.4 mm and very rarely up to 1 mm × 1 mm. The new mineral is transparent with greasy lustre. The mineral is very pale yellow to colourless in thin fragments to light yellow in aggregates. It is brittle, with imperfect {001} cleavage and an uneven fracture. Mohs’ hardness is ca. 6. Dcalc = 5.094 g cm–3. Under the microscope, percleveite-(La) is non-pleochroic, optically uniaxial (+), ω = 1.825(10) and ɛ = 1.835(10). The Raman spectrum is given. Chemical data (wt.%, electron-microprobe) are: La2O3 36.80, Ce2O3 31.22, Pr2O3 1.57, Nd2O3 2.96, SiO2 26.73, total 99.28. The empirical formula based on 7 O apfu is (La1.02Ce0.86Nd0.08Pr0.04)Σ2.00Si2.00O7. Percleveite-(La) is tetragonal, P41; the unit-cell parameters are: a = 6.8482(3), c = 24.8550(13) Å, V = 1165.64(11) Å3 and Z = 8. The strongest reflections in the powder X-ray diffraction pattern [d, Å(I)(hkl)] are: 4.194(18)(113), 3.564(16)(106), 3.349(16)(201,202), 3.157(100)(203,116,008), 3.043(22)(211), 2.934(39)(122), 2.893(29)(213) and 2.864(21)(117). The crystal structure of percleveite-(La) is solved from the single-crystal X-ray diffraction data [R = 0.0617 for 2831 unique reflections with I > 2σ(I)]. The new mineral is named as an analogue of percleveite-(Ce) with La predominance over the rare-earth elements.

Levantite, with the end-member formula KCa3(Al2Si3)O11(PO4), is the phosphate analogue of latiumite, KCa3(Al3Si2)O11(SO4, CO3) found in gehlenite–wollastonite hornfels on Har Parsa, Negev Desert, Israel. Levantite forms later zones on long-prismatic crystals of latiumite. Rarer homogeneous colourless levantite crystals up to 0.2 mm long and with mean composition (K0.94Ba0.01Na0.01□0.04)Σ1.00(Ca2.96Mg0.03)Σ2.99{(Si2.69Al2.06Fe3+0.16P0.06)Σ4.97O11}[(PO4)0.65(SO4)0.35]Σ1.00 were noted. Minerals of the levantite–latiumite series are associated with gehlenite, wollastonite, clinopyroxene of the esseneite–diopside series, anorthite and Ti-bearing andradite. Levantite crystalises in space group P21 with unit-cell parameters a = 12.1006(9) Å, b = 5.1103(4) Å, c = 10.8252(9) Å, β = 107.237(8)°, V = 639.34(9) Å3 and Z = 2. The structure of levantite is analogous to latiumite. It is formed by tetrahedral hybrid zweier double layers [(Si,Al)10O22] connected by Ca atoms. Three Ca atoms linked to different double layers are bridged over by (PO4) and minor (SO4) groups. K atoms reside in the cavities between two superimposed zweier double layers. The measured micro-indentation hardness of levantite gave VHN50 = 580(19) (mean of 14), range 550–611 kg/mm2, which correlates with 5 on the Mohs scale. Cleavage is good on (100). Twinning on (100) is polysynthetic or simple. The calculated density is 2.957 g cm–3. Levantite is optically negative with α = 1.608(2), β = 1.618(2), γ = 1.622(2) (λ = 589 nm), 2Vmeas. = 70(5)° and 2Vcalc. = 64.3°. Dispersion of the optical axes r > v is weak; the optical orientation is: Z = b, X ^ c = 22–27°; and it is non-pleochroic. Minerals of the levantite–latiumite series from Israel show characteristic Raman spectra with the main bands at 994 cm–1 [ν1(SO4)2–] and 945 cm–1 [ν1(PO4)3–]. The band intensity ν1(PO4)3–/ν1(SO4) ratio is well correlated with P and S contents in the investigated minerals. The strongest lines in the powder diffraction pattern [dobs, Å (I, %) (hkl)] are: 3.0762(100)(310), 2.8551(96)($\bar 2$13), 2.9704(92)($\bar 3$12), 2.8573(83)(013), 2.5552(66)(020), 2.8228(48)(212), 2.8893(40)(400), and 3.0634(30)(103).

A new phyllosilicate mineral, lipuite (IMA2014-085), has been discovered from the N'Chwaning III mine, Kalahari Manganese Fields, Northern Cape Province, Republic of South Africa. It occurs as platy, tabular, or granular crystals and veined agglomerate in association with Mn-bearing sugilite, taniajacoite, pectolite, richterite, norrishite and namansilite. Lipuite is dark red–brown with vitreous lustre, red streak, an estimated Mohs hardness of 5 and the measured density is 2.83(3) g/cm3. It is biaxial (+) and characterised by bright red to dark red colour in thin section with measured refractive indices in white light: α = 1.635(1), β = 1.653(1), γ = 1.670(1) and 2V = 86(2)°. The Raman spectra of lipuite are composed of over 21 bands at 109, 146, 162, 183, 206, 244, 288, 342, 362, 455, 496, 520, 552, 613, 669, 886, 930, 971, 1097, 3487 and 3540 cm–1. The empirical formula from microprobe analyses is (based on total number of cations = 27.5 and structural refinement): K1.12Na8.16(Mn4.77Fe0.07)Σ4.84Mg0.44[Si11.97O30(OH)4](PO4)0.94O2(OH)2·4H2O. The idealised formula is: KNa8Mn3+5Mg0.5[Si12O30(OH)4](PO4)O2(OH)2·4H2O.

Lipuite is orthorhombic, space group Pnnm, a = 9.080(3), b = 12.222(3), c = 17.093(5) Å, V = 1897.0(9) Å3 and Z = 2. The strongest powder X-ray diffraction peaks [d, Å (I) (hkl)] are: 9.965(40)(011), 2.938(33)(310), 2.895(100)(311), 2.777(38)(224), 2.713(53)(320), 2.483(32)(126), 2.086(35)(046) and 1.534(40)(446). The crystal structure of lipuite is characterised by sheets of SiO4 tetrahedra that are linked together along [010] by K+, Na+, Mn3+, Mg2+ and P5+ cations, as well as hydrogen bonds. These tetrahedral sheets consist of 14-membered rings of SiO4 tetrahedra that zigzag along [100]. The two independent Mn3+ cations are both octahedrally coordinated. They form five-membered, edge-shared octahedral clusters between the SiO4 tetrahedral sheets. Lipuite represents a rather unique structure type and its silicate tetrahedral sheets can be considered a derivative of the silicate sheets in mica.

The crystal structure of comancheite, Hg2+55N3–24(OH, NH2)4(Cl,Br)34, orthorhombic, space group Pnnm, a = 18.414(5), b = 21.328(6), c = 6.6976(19) Å, V = 2630(2) Å3, Z = 1, was solved by direct methods and refined to an R1 index of 4.3% based on 4160 unique observed reflections. In the structure of comancheite, there are nine crystallographically distinct Hg2+ cations, each of which is coordinated by two N3– anions to form near-linear N3––Hg2+–N3– groups. Four other crystallographically distinct Hg2+ cations are coordinated by a mixture of N3–, O2–, (OH)– and (NH2)– anions, and there is a small amount of [Hg–Hg]2+ dimer. In addition, there are eight crystallographically distinct halogen sites, three of which are completely occupied by Cl–, and five of which are occupied by both Cl– and Br–. The principal anion, N3–, shows a strong preference for tetrahedral coordination by Hg2+, which results in a strongly bonded three-dimensional {–Hg2+–N3––} framework. This framework is both interrupted and contains large interstices that incorporate additional Hg2+ cations, a very small amount of [Hg+–Hg+]2+ dimer and additional anion species, O2–, (OH)– and (NH2)–, that coordinate Hg2+.

Comancheite was described originally as an Hg-oxide mineral. The major change in chemical composition indicated by the present work was approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (Voting Proposal 13-B). The presence of N provides some analytical challenges, particularly in the presence of Hg. New bond-valence parameters were derived for Hg2+–N3– bonds [Ro(N3–) = 1.95] using well refined Hg2+ structures, and this allows discrimination between Hg2+–O2– and Hg2+–N3– bonds based on the valence-sum rule. Comparison of the Raman spectra of several Hg-bearing minerals shows that peaks in the range 500–700 cm–1 are characteristic of Hg2+–N3– stretching vibrations whereas peaks in the range 350–500 cm–1 are characteristic of Hg2+–O2– stretching vibrations; Hg2+–O2– and Hg2+ – N3– bonds may be discriminated on this basis.

Beusite-(Ca), ideally Ca${\rm Mn}_{\rm 2}^{2 +} $(PO4)2, is a new graftonite-group mineral from the Yellowknife pegmatite field, Northwest Territories, Canada. It occurs in a beryl–columbite–phosphate rare-element pegmatite where it is commonly intergrown with triphylite–lithiophilite or sarcopside, and may form by exsolution from a high-temperature (Li,Ca)-rich graftonite-like parent phase. It occurs as pale-brown lamellae 0.1–1.5 mm wide in triphylite, and is pale brown with a vitreous lustre and a very pale-brown streak. It is brittle, has a Mohs hardness of 5, and the calculated density is 3.610 g/cm3. Beusite-(Ca) is colourless in plane-polarized light, and is biaxial (+) with α = 1.685(2), β = 1.688(2), γ = 1.700(5), and the optic axial angle is 46.0(5)°. It is non-pleochroic with X || b; Y ˄ a = 40.3° in β obtuse; Z ˄ a = 49.7° in β acute. Beusite-(Ca) is monoclinic, has space group P21/c, a = 8.799(2), b = 11.724(2), c = 6.170(1) Å, β = 99.23(3)°, V = 628.3(1) Å3 and Z = 4. Chemical analysis by electron microprobe gave P2O5 41.63, FeO 19.43, MnO 23.63, CaO 15.45, sum 100.14 wt.%. The empirical formula was normalized on the basis of 8 anions pfu: (Ca0.94Fe0.92Mn1.13)Σ2.99(PO4)2.00. The crystal structure was refined to an R1 index of 1.55%. Beusite-(Ca) is a member of the graftonite group with Ca completely ordered at the [8]-coordinated M(1) site.

Dargaite, ideally BaCa12(SiO4)4(SO4)2O3, is an additional member of the arctite group belonging to minerals with a modular intercalated antiperovskite structure derived from hatrurite. The holotype specimen was found at a small outcrop of larnite pseudoconglomerates in the Judean Mts, West Bank, Palestinian Autonomy. Larnite, fluorellestadite–fluorapatite, brownmillerite, fluormayenite–fluorkyuygenite and ye'elimite are the main minerals of the holotype specimen; ternesite, shulamitite and periclase are noted rarely. Dargaite, nabimusaite and gazeevite occur in linear zones with higher porosity within larnite rocks. Pores are filled with ettringite and Ca-hydrosilicates, less commonly with gibbsite, brucite, baryte, katoite and calciolangbeinite. Dargaite is colourless, transparent with a white streak and has a vitreous lustre. It exhibits pronounced parting and imperfect cleavage along (001). Mohs’ hardness is ~4.5–5.5. The empirical formula is (Ba0.72K0.24Na0.04)Σ1(Ca11.95Mg0.04Na0.01)Σ12([SiO4]0.91 [PO4]0.05[AlO4]0.03[Ti4+O4]0.01)Σ4([SO4]0.84[PO4]0.14[CO3]0.02)Σ2(O2.54F0.46)Σ3. Dargaite is trigonal R$\overline 3 $m, the unit-cell parameters are: a = 7.1874(4) Å, c = 41.292(3) Å, V = 1847.32(19) Å3 and Z = 3. The crystal structure of dargaite was refined from X-ray single-crystal data to R1 = 3.79%. The calculated density is 3.235 g cm–3. The following main Raman bands are distinguished on the holotype dargaite (cm–1): 122, 263, 323, 464, 523, 563, 641 and 644, 829 and 869, 947, 991 and 1116. The formation conditions of dargaite are linked to the local occurrence of pyrometamorphic by-products (gases, fluids and melts) transforming earlier mineral associations at ~900°C.

The new mineral nabimusaite, KCa12(SiO4)4(SO4)2O2F (R3m, a = 7.1905(4), c = 41.251(3) Å, V = 1847.1(2) Å3, Z = 3), has been discovered in larnite-ye' elimite nodules of pyrometamorphic rocks of the Hatrurim Complex. Nabimusaite is colourless, transparent with a white streak, has a vitreous lustre and does not show luminescence. It is brittle, but shows pronounced parting and imperfect cleavage along (001). Nabimusaite is uniaxial (–), ω = 1.644(2), ε = 1.640(2) (589 nm), nonpleochroic, Mohs' hardness is ∼5 and the calculated density is 3.119 g cm–3. The crystal structure has been solved and refined to R1 = 0.0416. Its artificial analogue is known. The nabimusaite structure may be derived from that of hatrurite, also known as the clinker phase 'alite' (C3S = Ca3SiO5), and is built up by an intercalation of three positively charged hatrurite-like modules of composition [Ca12(SiO4)4O2F]3+ with inserted modules of [K(SO4)2]3–. The hatrurite-like modules in nabimusaite are characterized by octahedrally coordinated anion sites and tetrahedrally coordinated cation sites. The structure is representative of the intercalated antiperovskite type. In contrast to its synthetic analogue, nabimusaite is P-bearing. The shortened bond T–O lengths for one tetrahedral site indicates P preference at the Si2 site, located at the border of the hatrurite-like modules. Significant variations of isomorphous substitutions in nabimusaite suggest the possibility of other isostructural minerals occurring in Nature. It also seems likely that nabimusaite could serve as a prototype for new advanced synthetic materials, given the discovery of two other new minerals in the Hatrurim Complex with related modular structures, placed in the nabimusaite group. These are zadovite and aradite, as described in a companion paper (Galuskin et al., 2015a).

The mineral assemblage and paragenesis of nabimusaite suggests that nabimusaite formed as a result of the reaction of potassium-enriched, sulfate-bearing melt with larnite and ellestadite. This contradicts the isochemical model that pyrometamorphic rocks of the Hatrurim Complex formed relatively fast in a practically dry system.

Nolzeite, Na(Mn,□)2[Si3(B,Si)O9(OH)2]·2H2O, is a new mineral found in altered sodalite syenite at the Poudrette quarry, La Vallée-du-Richelieu, Montérégie (formerly Rouville County), Québec, Canada. Crystals are colourless to pale green and are acicular with average dimensions of 5 μm × 8 μm × 55 μm. They occur as radiating to loose, randomly oriented groupings within vugs associated with aegirine, nepheline, sodalite, eudialyte-group minerals, analcime, natron, pyrrhotite, catapleiite, steedeite and the unidentified mineral, UK80. Nolzeite is non-pleochroic, biaxial, with nmin = 1.616(2) and nmax = 1.636(2) and has a positive elongation. The average of six chemical analyses gave the empirical formula: Na1.04(Mn1.69□0.24Fe0.05Ca0.02)∑=2.00(Si2.96S0.04)∑=3.00(B0.70Si0.30)∑=1.00O9(OH)2·2H2O based on 13 anions. The Raman spectrum shows six distinct bands occurring at ∼3600–3300 cm–1 and 1600–1500 cm–1 (O–H and H–O–H bending), 1300–1200 cm–1 (B–OH bending), 1030–800 cm–1 (Si–O–Si stretching) as well as 700–500 cm–1 and 400–50 cm–1 (Mn–O and Na–O bonding, respectively). The FTIR spectrum for nolzeite shows bands at ∼2800 –3600 cm–1(O–H) stretching, a moderately sharp band at 1631 cm –1(H–O–H) bending, strong, sharp bands at ∼650 –700 cm–1, ∼800 –840 cm–1, and ∼900–1100 cm–1(Si–O and B –O) bonds. Nolzeite is triclinic, crystallizing in space group P with a = 6.894(1), b = 7.632(2), c = 11.017(2) Å, α= 108.39(3), β= 99.03, γ = 103.05(3)°, V = 519.27 Å3, and Z = 2. The crystal structure was refined to R = 12.37% and wR2 = 31.07% for 1361 reflections (Fo > 4σFo). It is based on chains of tetrahedra with a periodicity of three (i.e. a dreier chain) consisting of three symmetrically independent SiO4 tetrahedra forming C-shaped clusters closed by BO2(OH)2 tetrahedra, producing single loop-branched dreier borosilicate chains. The chains are linked through shared corners to double chains of edge-sharing MnO5(OH) octahedra. Nolzeite is a chain silicate closely related to steedeite and members of the sérandite–pectolite series. Paragenetically, nolzeite is late-stage, probably forming under alkaline conditions and over a narrow range of low pressures and temperatures.