New data on the isomorphism of extra-framework components (including chromophores) in two- and multilayer minerals belonging to the cancrinite and sodalite groups, are obtained using chemical and single-crystal X-ray diffraction data as well as infrared, Raman, ESR, UV–Vis–near IR absorption and photoluminescence spectroscopy methods. It is shown that the blue color of these minerals may be due to CO₃^•− or S₃^•− radical anions, whereas yellow and pink shadings are typically due to the presence of S₂^•− radical anions and S₄^•− or S₄, respectively. Two kyanoxalite varieties are distinguished: (1) with predominantly acid oxalate groups and (2) predominantly neutral oxalate groups. Zundel cation H₅O₂+ and CO₂ molecules are shown to be typical impurities in nosean. The Zundel cation is also detected in kyanoxalite and in the 12-layer, cancrinite-related mineral marinellite. Wide isomorphic series involving substitutions of SO₄⁻ for SO₃²⁻ and CO₃²⁻, as well as OH⁻ for H₂O and F⁻, are common for eight-layer, cancrinite-group minerals with an afghanite-type framework.

This paper is the first description of natural copper-rich oxide spinels. They were found in deposits of oxidizing-type fumaroles related to the Tolbachik volcano, Kamchatka, Russia. This mineralization is represented by nine species with the following maximum contents of CuO (wt.%, given in parentheses): a new mineral thermaerogenite, ideally CuAl₂O₄ (26.9), cuprospinel, ideally CuFe³⁺₂O₄ (28.6), gahnite (21.4), magnesioferrite (14.7), spinel (10.9), magnesiochromite (9.0), franklinite (7.9), chromite (5.9), and zincochromite (4.8). Cuprospinel, formerly known only as a phase of anthropogenic origin, turned out to be the Cu-richest natural spinel-type oxide [sample with the composition (Cu_0.831Zn_0.100Mg_0.043Ni_0.022)_Σ0.996(Fe³⁺_1.725Al_0.219Mn³⁺_0.048Ti_0.008)_Σ2.000O₄ from Tolbachik]. Aluminum and Fe³⁺-dominant spinels (thermaerogenite, gahnite, spinel, cuprospinel, franklinite, and magnesioferrite) were deposited directly from hot gas as volcanic sublimates. The most probable temperature interval of their crystallization is 600–800 °C. They are associated with each other and with tenorite, hematite, orthoclase, fluorophlogopite, langbeinite, calciolangbeinite, aphthitalite, anhydrite, fluoborite, sylvite, halite, pseudobrookite, urusovite, johillerite, ericlaxmanite, tilasite, etc. Cu-bearing spinels are among the latest minerals of this assemblage: they occur in cavities and overgrow even alkaline sulfates. Cu-enriched varieties of chrome-spinels (magnesiochromite, chromite, and zincochromite) were likely formed in the course of the metasomatic replacement of a magmatic chrome-spinel in micro-xenoliths of ultrabasic rock under the influence of volcanic gases. The new mineral thermaerogenite, ideally CuAl₂O₄, was found in the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption. It forms octahedral crystals up to 0.02 mm typically combined in open-work clusters up to 1 mm across. Thermaerogenite is semitransparent to transparent, with a strong vitreous lustre. Its colour is brown, yellow-brown, red-brown, brown-yellow or brown-red. The mineral is brittle, with the conchoidal fracture, cleavage is none observed. D(calc.) is 4.87 g/cm³. The chemical composition of the holotype (wt.%, electron microprobe) is: CuO 25.01, ZnO 17.45, Al₂O₃ 39.43, Cr₂O₃ 0.27, Fe₂O₃ 17.96, total 100.12 wt.%. The empirical formula calculated on the basis of 4 O apfu is: (Cu_0.619Zn_0.422)_Σ1.041(Al_1.523Fe³⁺_0.443Cr_0.007)_Σ1.973O₄. The mineral is cubic, Fd-3m, a = 8.093(9) Å, V = 530.1(10) ų. Thermaerogenite forms a continuous isomorphous series with gahnite. The strongest lines of the powder X-ray diffraction pattern of thermaerogenite [d, Å (I, %) (hkl)] are: 2.873 (65) (220), 2.451 (100) (311), 2.033 (10) (400), 1.660 (16) (422), 1.565 (28) (511) and 1.438 (30) (440).

Ferrisanidine, K[Fe³⁺Si₃O₈], the first natural feldspar with species-defining iron, is an analogue of sanidine bearing Fe³⁺ instead of Al. It was found in exhalations of the active Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Fissure Tolbachik Eruption, Tolbachik volcano, Kamchatka Peninsula, Russia. The associated minerals are aegirine, cassiterite, hematite, sylvite, halite, johillerite, arsmirandite, axelite, aphthitalite. Ferrisanidine forms porous crusts composed by cavernous short prismatic crystals or irregular grains up to 10 μm × 20 μm. Ferrisanidine is transparent, colorless to white, the lustre is vitreous. D_calc is 2.722 g·cm⁻³. The chemical composition of ferrisanidine (wt. %, electron microprobe) is: Na₂O 0.25, K₂O 15.15, Al₂O₃ 0.27, Fe₂O₃ 24.92, SiO₂ 60.50, in total 101.09. The empirical formula calculated based on 8 O apfu is (K_0.97Na_0.03)_Ʃ1.00(Si_3.03Fe³⁺_0.94Al_0.02)_Ʃ3.99O₈. The crystal structure of ferrisanidine was studied using the Rietveld method, the final R indices are: R_p = 0.0053, R_wp = 0.0075, R₁ = 0.0536. Parameters of the monoclinic unit cell are: a = 8.678(4), b = 13.144(8), c = 7.337(5) Å, β = 116.39(8)°, V = 749.6(9) ų. Space group is C2/m. The crystal structure of ferrisanidine is based on the sanidine-type “ferrisilicate” framework formed by disordered [SiO₄] and [Fe³⁺O₄] tetrahedra.

Three generations of tourmaline have been identified in propylite in the Vetka porphyry copper-molybdenum deposit of the Chukchi Peninsula of Russia. Tourmaline-I is characterized by its Fe_tot/(Fe_tot + Mg) value, which ranges from 0.33 to 0.49. Tourmaline-II, which crystallizes at a lower temperature, overgrowing tourmaline-I or occurring as isolated crystals, is distinguished by a higher Fe_tot/(Fe_tot + Mg), which varies from 0.46 to 0.72. The Fe_tot/(Fe_tot + Mg) ratio in tourmaline-III, which overgrows tourmaline-II is lower (0.35–0.49), and is identical to that of the first tourmaline generation. This is probably caused by the beginning of sulfide deposition. Tourmalines in the deposit characterized by complex isomorphic substitutions can be attributed to the intermediate members of the dravite—“hydroxy-uvite”-“oxy-uvite” and schorl-“hydroxy-feruvite”-“oxy-feruvite” series. Tourmaline starts to crystallize at temperatures above 340°C. The fluid responsible for the tourmaline deposition was magmatic, with a significant admixture of meteoric water (δ¹⁸O_{H 2}O = −0.85 to −0.75‰). The high Fe³⁺/Fe_tot ratio (0.50) indicates high oxygen activity when the tourmaline precipitated. It has been established that the isomorphic substitution Fe_tot → Al is typomorphic of tourmalines from porphyry copper deposits worldwide.

A multimethodic approach based on infrared, Raman, electron spin resonance and photoluminescence spectroscopy, absorption spectroscopy in near infrared, visible and ultraviolet regions, single-crystal X-ray diffraction as well as electron microprobe analyses was applied to the characterization of a new commensurately modulated cubic haüyne analogue with the modulation parameter of 0.2 and unit-cell parameter of 45.3629(3) Å (designated as haüyne-45Å) from the Malobystrinskoe lazurite deposit, in the Baikal Lake area, Siberia, Russia, as well as associated SO₃²⁻-bearing afghanite. Haüyne-45Å is the second member, after vladimirivanovite, of the sodalite group with a commensurately modulated structure. The average structure is based on the tetrahedral aluminosilicate sodalite-type framework with sodalite cages of different sizes. The simplified formula of haüyne-45Å is Na₆Ca_2−x(Si₆Al₆O₂₄)(SO₄²⁻,HS⁻,S₂^●−,S₄,S₃^●−,S₅²⁻)_2−y. The structural modulations of the haüyne-45Å framework are presumably related to the regular alternation of SO₄²⁻ anions with polysulfide S₂^●−, S₃^●−, S₄, and S₅²⁻ groups detected by the spectroscopic methods. Mechanisms of thermal conversions of S-bearing groups in haüyne-45Å under oxidizing and reducing conditions at temperatures up to 800 °C are studied, and their geochemical importance is discussed.

Two new isostructural minerals udinaite and arsenudinaite with the end-member formulae NaMg₄(VO₄)₃ and NaMg₄(AsO₄)₃, respectively, are found in the Arsenatnaya fumarole, Tolbachik volcano, Kamchatka, Russia. They are associated with one another and anhydrite, diopside, hematite, schäferite, berzeliite, svabite, calciojohillerite, tilasite, reznitskyite, ludwigite, rhabdoborite-group borates, forsterite, magnesioferrite, fluorapatite, pliniusite, and powellite. Both minerals occur as equant tetragonal prismatic–dipyramidal crystals up to 0.15 mm, aggregates up to 1 cm and interrupted crusts up to 2 × 2 cm². Udinaite and arsenudinaite, visually indistinguishable from one another, are transparent, beige or brownish-yellowish, with vitreous lustre. Both minerals are optically uniaxial (–); ω = 1.785/1.777 and ε = 1.830/1.820, D_calc. = 3.613/3.816 g·cm⁻³ (udinaite/arsenudinaite). The empirical formulae are: udinaite: (Na_0.55Ca_0.16)_Σ0.71(Mg_4.04Mn_0.02Fe_0.01)_Σ4.07(V_1.63As_1.05P_0.28Si_0.03S_0.01)_Σ3.00O₁₂; arsenudinaite: (Na_0.57Ca_0.13)_Σ0.70(Mg_4.01Mn_0.01Fe_0.01)_Σ4.03(As_2.07V_0.84P_0.10Si_0.01S_0.01)_Σ3.03O₁₂. Both minerals are tetragonal, I-42d, Z = 4, a = 6.8011(2)/6.8022(1), c = 19.1839(12)/19.1843(6) Å, and V = 887.35(7)/887.66(4) ų, R₁ = 0.0287/0.0119 (udinaite/arsenudinaite). Their crystal structure consists of the helical chains of edge-sharing MgO₆ octahedra and isolated TO₄ tetrahedra, forming a heteropolyhedral pseudo-framework with Na cations located in cavities. Both minerals are isostructural to jeffbenite. Udinaite and arsenudinaite form an isomorphous series in which the contents of T constituents vary within (in apfu): V_1.6–0.1As_2.8–1.0P_0.4–0.0.