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Niksergievite, [[Ba.sub.1.33][Ca.sub.0.67]Al(C[O.sub.3])[(OH).sub.4]] [Al.sub.2]([Al[Si.sub.3][O.sub.10])[(OH).sub.2]]*n[H.sub.2]O, is a new phyllosilicate closely related to the surite-ferrisurite series. It was found at the--400 m level of the Tekeli Pb-Zn mine, southeast Kazakhstan (44[degrees] N, 78[degrees] E). The mineral occurs as curved plates 3-5 mm in size forming rosette-like aggregates up to 5 cm across. Associated minerals include calcite, quartz, dolomite, celsian, sphalerite, pyrite, barite, and montmorillonite. Niksergievite is white with a light greenish tint and pearly luster on cleavage planes. The streak is white and the mineral is non-fluorescent. The Mohs hardness is 1-1 1/2. The cleavage is perfect (mica-like) on {001}. [D.sub.m] = 3.16 g/[cm.sup.3] and [D.sub.x] = 3.21 g/[cm.sup.3]. The IR spectrum shows the following peaks (* shoulder): 3665*, 3640, 3405, 1630, 1454, 1105*, 1080*, 1035, 1020*, 980*, 960*, 920*, 876, 835*, 750*, 704, 625*, 560*, 535, 474, and 417 [cm.sup.-1]. Optically, the mineral is colorless, non-pleochroic, biaxial (-), 2V= 0-10[degrees], [alpha] = 1.580(2), [beta] = 1.625(2), [gamma] = 1.625(2), and X ~ c. The chemical composition (electron microprobe, C[O.sub.2] and [H.sub.2]O by TGA) is [K.sub.2]O 0.1, CaO 5.1, BaO 27.1, MgO 0.4, FeO 0.2, [Al.sub.2][O.sub.3]24.8, Si[O.sub.2] 28.7, C[O.sub.2] 6.1, and [H.sub.2]O 8.3, with a total of 100.8 wt%. The empirical formula based on (Si + Al + Mg + Fe) = 7 is [([Ba.sub.1.27][Ca.sub.0.65] [K.sub.0.02]).sub.1.92][([Al.sub.3.49][Si.sub.3.42][Mg.sub.0.07] [Fe.sup.2+.sub.0.02].sub.7.00][O.sub.10.00][(C[O.sub.3].sub.0.99] [(OH).sub.6.20]*0.20[H.sub.2]O. The simplified formula is [(Ba,Ca).sub.2][(Al,Si).sub.7][O.sub.10](C[O.sub.3])[(OH).sub.6] *n[H.sub.2]O and the proposed structural formula is [[Ba.sub.1.33] [Ca.sub.0.67]Al(C[O.sub.3])[(OH).sub.4]][[Al.sub.2](Al[Si.sub.3] [O.sub.10])(OH).sub.2]*n[H.sub.2]O. The mineral is monoclinic, C2/c, C2, or Cm, a 5.176(3), b 8.989(3), c 16.166(5) [Angstrom], [beta] 96.44(6)[degrees], V 747.4(9) [[Angstrom].sup.3], Z = 2. The strongest reflections in the X-ray powder diffraction pattern are as follows [d in [Angstrom], (I) (hkl)]: 16.1 (40)(001), 4.49(90)(020), 3.68(60) (014,113), 2.585(100)(130,201, 131), 2.230(90)(134,220), 2.069 (80)(043), 1.692(60)(311,151,240). It is named in honor of Prof. Nikolai Grigorievich Sergiev (1901-1960) for his contributions to the geology of Kazakhstan.

The crystal structure of glagolevite, Na[(Mg,Al).sub.6][[Si.sub.3]Al[O.sub.10]][(OH,O).sub.8], a new mineral from the Kovdor alkaline massif, Kola peninsula, Russia, has been solved and refined to [R.sub.1] = 0.117, calculated from 1503 unique observed reflections ([F.sub.o] [greater than or equal to] 4[sigma][F.sub.o]), and to [R.sub.1] = 0.118 for all 1550 unique reflections. The specimen contained several polytypes; the crystal studied yielded triclinic space group C1, a = 5.3580(11), b = 9.2810(19), c = 14.574(3) [Angstrom], [alpha] = 90.00(3), [beta] = 97.08(3), [gamma] = 90.00(3)[degrees], V = 719.2(3) [[Angstrom].sup.3]. Glagolevite is the first mineral of the chlorite group that contains Na atoms located between the 2:1 layers and the interlayer octahedral sheets. The Na atoms are in sevenfold coordination. The Na[(O,OH).sub.7] polyhedron is a trigonal prism with one of the triangular bases extended to a square. The tetrahedral sheets show disorder owing to polytype intergrowths. Tetrahedral site occupancies correlate with the occupancies of the Na sites. The polytypic composition of the crystal studied is estimated at 57% IIb-6, 31% IIb-2, and 12% IIb-4.

The new sodalite-group mineral sapozhnikovite, ideally Na8(Al6Si6O24)(HS)2, was discovered in a hydrothermally altered urtite-like rock at Karnasurt Mountain, Lovozero alkaline massif, Kola Peninsula, Russia. The associated minerals are nepheline, aegirine, potassic feldspar, albite, kyanoxalite, natrolite, fluorapatite, fluorcaphite, lomonosovite (partially or completely altered to murmanite) and loparite-(Ce). Sapozhnikovite forms isolated colourless to pale greyish anhedral equant grains up to 5 mm across. The streak is white and the lustre is vitreous. Strong orange fluorescence under longwave UV radiation (λ = 330 nm) and weak yellow-orange fluorescence under shortwave UV radiation (λ = 245 nm) is observed. Sapozhnikovite is brittle, with a Mohs hardness of 5½. Cleavage is imperfect on (110). Density measured by flotation in heavy liquids is equal to 2.25(1) g⋅cm–3. The calculated density is 2.255 g⋅cm–3. Sapozhnikovite is characterised by infrared, Raman, electron spin resonance, NIR-Vis-UV absorption, and photoluminescence spectroscopy. The chemical composition is (wt.%, electron microprobe, H2O determined by gas chromatography of ignition products): Na2O 25.05, Al2O3 32.44, SiO2 37.58, HS 4.33, Cl 2.22, H2O 0.30, –O≡(Cl,HS) –1.55, total 100.37. The empirical formula is Na7.73Al6.08Si5.97O24(HS)1.25Cl0.60⋅0.16H2O. The crystal structure was determined using single-crystal X-ray diffraction data and refined to R1 = 1.62%. Sapozhnikovite is cubic, P $\bar{4}$ 3n, with a = 8.9146(1) Å, V = 708.45(2) Å3 and Z = 1. The new mineral is isostructural with sodalite. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 6.30 (37) (110), 3.638 (100) (211), 2.821 (14) (310), 2.572 (18) (222), 2.382 (16) (321) and 2.101 (29) (411). The mineral is named in honour of the Russian mineralogist and crystallographer Dr. Anatoly Nikolaevich Sapozhnikov (b. 1946). [ABSTRACT FROM AUTHOR]

The new cancrinite-group mineral steudelite, ideally (Na3☐)[(K,Na)17Ca7]Ca4(Al24Si24O96)(SO3)6F6·4H2O, was discovered in syenite ejectum from the Sacrofano paleovolcano, Latium region, Italy. The associated minerals are sanidine, diopside, andradite, biotite, leucite, haüyne, sacrofanite, biachellaite, liottite, and secondary dioctahedral smectite. Steudelite forms colourless, thick-tabular, isometric and short-prismatic crystals up to 7 mm across. Cleavage is distinct on {10 1 ¯ 0}; perfect parting on {0001} is observed. Steudelite is brittle, with uneven fracture. The Mohs' hardness is 5. Measured and calculated density are equal to 2.51 (1) and 2.511 g cm–3, respectively. The IR spectrum shows the presence of H2O molecules, SO32– and minor SO42– anionic groups. The chemical composition of steudelite is (wt%; electron microprobe, H2O determined by the modified Penfield method; total sulfur apportioned between SO2 and SO3 based on structural data): Na2O 7.40, K2O, 8.42, CaO 3.54, Al2O3 26.46, Fe2O3 0.18, SiO2 30.96, SO2 4.74, SO3 5.18, F 1.66, Cl 0.84, H2O 1.6, –O≡Cl,F − 0.89, total 100.09. The empirical formula is H8.22Na11.06K8.28Ca11.18(Al24.04Fe3+0.10Si23.86O96)(SO3)3.43(SO4)3.00F4.04Cl1.10O3.89. The crystal structure of steudelite is based on the afghanite-type aluminosilicate framework containing a column of cancrinite cages and isolated cancrinite and liottite cages whose populations are {Na3.14Ca0.14☐0.72[(H2O,OH)3.72Cl0.28]}, {Ca4F4.02Cl0.60}, and {K8.40Na8.13Ca7.10(SO3)3.24(SO4)2.76}, respectively. The SO32– and SO42– groups occur in the liottite cage, at two sites with the occupancies S1[(SO4)0.69(SO3)0.31] and S2[SO3]2. Steudelite is hexagonal, space group P-62c, with a = 12.89529 (15), c = 21.2778 (3) Å, V = 3064.21 (8) Å3, and Z = 1. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %) (hkl)] are: 11.15 (28) (100), 4.799 (25) (104), 3.973 (16) (105), 3.721 (47) (300), 3.305 (100) (214, 303, 400), 2.661 (17) (008), 2.149 (21) (330). The mineral is named in honour of the outstanding German chemist, a specialist in chemistry of sulfur Prof. Ralf Steudel (1937–2021). [ABSTRACT FROM AUTHOR]

The new wermlandite-group mineral erssonite, ideally CaMg7Fe3+2(OH)18(SO4)2⋅12H2O (or [Mg7Fe3+2(OH)18][Ca(SO4)2]⋅12H2O), was discovered in a late-stage, low-temperature assemblage in cavities of a magnetite-bearing dolomitic rock from the Långban deposit, Värmland county, Bergslagen ore province, Sweden. The associated minerals are dolomite, calcite, members of the magnetite–magnesioferrite solid-solution series, phlogopite, chrysotile, pyroaurite and norbergite. Erssonite has a vitreous lustre and forms colourless, platy hexagonal crystals flattened on [0001], up to 0.5 mm across and up to 10 μm thick, occurring mainly as aggregates in cavities of dolomitic rock. Erssonite is malleable; separate crystals are flexible and non-elastic, with a perfect, mica-like cleavage on {0001}. The calculated density is equal to 2.02 g⋅cm–3. Raman spectroscopy shows the presence of typical bands for S–O bonds attributed to intercalated SO42– anions and structural OH– anions together with the absence of C–O bonds, attributed to carbonate anions. The chemical composition is (wt.%, electron microprobe, H2O content is calculated from structure data): MgO 28.67, CaO 2.76, Al2O3 0.23, Cr2O3 0.23, Fe2O3 16.00, SiO2 0.48, SO3 14.80, H2O 35.58, total 98.75. The empirical formula based on 38 O atoms is H41.48Ca0.52Mg7.47Fe3+2.11Al0.05Cr0.03S1.94Si0.08O38. The ideal formula is CaMg7Fe3+2(OH)18(SO4)2⋅12H2O or {Mg7Fe3+2(OH)18}{[Ca(H2O)6](SO4)2(H2O)6}. The crystal structure was determined using single-crystal X-ray diffraction data and refined to R = 0.093. Erssonite is trigonal, P $\bar{3}$ c1, with a = 9.3550(6), c = 22.5462(14) Å, V = 1708.8(2) Å3 and Z = 2. The strongest lines of the powder X-ray diffraction pattern [d, Å (I, %)(hkl)] are: 11.22 (90)(002), 5.63 (64)(004), 4.670 (100)(110, 104, 014), 2.626 (64)(032, 302), 2.435 (66)(034, 304) and 1.951 (45)(038, 308). The mineral is named in honour of the Swedish amateur mineralogist Dr. Anders Ersson (b. 1971). [ABSTRACT FROM AUTHOR]

The new beudantite-group mineral oberwolfachite, ideally SrFe3+3(AsO4)(SO4)(OH)6, was discovered in two localities: Clara mine, Oberwolfach, Schwarzwald, Baden-Württemberg, Germany (holotype) and Monterniers mine, Lantignié, Rhône, Auvergne-Rhône-Alpes, France (cotype). The associated minerals are quartz, baryte, hematite, illite, goethite, beudantite and dussertite (Clara) and arsenogoyazite, jarosite, graulichite-(Ce), goethite and hematite (Monterniers). Oberwolfachite forms yellow to brown platy crystals up to 1 mm across or thick outer zones of mixed (oberwolfachite–beudantite) crystals up to 3 mm across. The lustre is adamantine and the streak is yellow. A distinct cleavage on {0001} is observed. Calculated density is 3.874 g⋅cm–3. The infrared spectra are given. The chemical composition of the holotype/cotype samples are (wt.%, b.d.l. = below detection limit): K2O 1.25/1.86, SrO 6.41/11.15, BaO 8.13/0.45, PbO 2.18/b.d.l., Al2O3 0.16/0.23, Fe2O3 38.99/39.98, La2O3 1.68/not determined, Ce2O3 1.28/2.06, P2O5 0.12/b.d.l., As2O5 17.55/16.55, SO3 12.86/14.99, H2O (calculated) 8.72/9.05, total 99.33/96.62. The empirical formula of the holotype sample is (Sr0.38Ba0.33K0.16Pb0.06La0.06Ce0.05)Σ1.04(Fe3+3.03Al0.02)Σ3.05[(SO4)1.00(AsO4)0.95(PO4)0.01](O6.16H6.00). The crystal structures of both samples were determined using single-crystal X-ray diffraction data and refined to R = 3.13% (holotype, 293 K) and 2.65% (cotype, 170 K). Oberwolfachite is trigonal, R ${\bar 3}$ m, with a = 7.3270(3) Å, c = 17.0931(9) Å and V = 794.70(8) Å3 (holotype), and a = 7.298(2) Å, c = 16.908(3) Å and V = 779.8(4) Å3 (cotype); Z = 3. The strongest lines of the powder X-ray diffraction pattern of holotype [d, Å (I, %)(hkl)] are: 5.95 (56)(101), 3.664 (37)(110), 3.117 (16)(021), 3.082 (100)(113), 2.548 (15)(024), 2.280 (22)(107), 1.983 (26)(303) and 1.832 (19)(220). [ABSTRACT FROM AUTHOR]