Vol CLII, No 2 (2023)

Townendite, ideally Na₈ZrSi₆O₁₈, earlier considered as an extremely rare mineral, is found in large amount in a hyperagpaitic pegmatoid aegirine-nepheline-sodalite-microcline rock with eudialyte, kazakovite, villiaumite, lomonosovite and alkali sulfides in deep levels at Mt. Kar-nasurt, Lovozero alkaline pluton, Kola peninsula, Russia. Townendite forms transparent lilac to light violet segregations up to 6 × 4 cm. Its crystal structure was studied on single-crystal XRD data, R₁ = 2.29%. The mineral is trigonal, R-3m, a = 10.2910(3), c = 13.1577(4) Å, V = = 1206.77(7) ų, and Z = 3. The simplified crystal chemical formula derived from the structure refinement is: ^ANa₃^B(Na_2.7□_0.3)_Σ3^C(Na_1.8Mn_0.2)_Σ2^MZrSi₆O₁₈. The IR spectrum shows only trace amount of OH groups. Townendite serves as a proto-phase for the formation in nature of Ca- and Mn-poor (Ca + Mn < 0.5 apfu) OH-bearing lovozerite-group zirconosilicates. Two different in crystal chemical mechanism natural evolution series are found: (1) townendite ^ANa₃^BNa₃^CNa₂^MZrSi₆O₁₈ → kapustinite ^ANa₃^B(Na_2–3□_0–1)^C□₂^MZrSi₆O_15–16(OH)_2–3 → → litvinskite ^A(Na_2–3□_0–1)^B(□,H₂O)₃^C□₂^MZrSi₆O_13–14(OH)_5–6; (2) townendite → zolotarevite ^ANa₃^B(H₂O,□)₃^CNa₂^MZrSi₆O₁₅(OH)₃ → litvinskite. The abundance of products of townendite alteration in near-surface rocks of the Lovozero complex shows that this mineral is widespread in deep levels of the pluton in “fresh” peralkaline intrusive rocks and pegmatites and is (1) a bright indicator of extremally high agpaicity and (2) an important, sporadically main concentrator of Zr and Hf in them. The major amount of townendite occurs in unaltered rocks of the fifth intrusive phase of the Lovozero pluton which are protholith rocks of the well-known porphyry-like lovozerite lujavrites.

The Late Jurassic late-orogenic volcanogenic-plutonogenic Darasun deposit of the gold-sulphide-quartz formation holds Au–Bi and post-gold Sb mineralizations. Carbonate-quartz-sulfide veins in Western part of the deposit are surrounded by listvenite rims. Their golden ores were formed under conditions of low activity of S₂, they contain pyrrhotine, arsenopyrite, chalcopyrite, pyrite, bismuthate I (Bi_1.89–1.98Sb_0.11–0.02)₂S₃, galenobismuthite, nests of bismuth and ikunolite Bi₄S₃. There is observed exsolution of ikunolite mainly into the native bismuth (Bi_0.98–1Sb_0.02–0) and bismuthite-II; the composition of bismuthite-II in center of aggregates with the bismuth is (Bi_1.96–1.97Sb_0.04–0.03)₂S₃, whereas the composition on their periphery is an more antimonian one is (Bi_1.91–1.92Sb_0.09–0.08)₂S₃. While the high fineness gold (970–935 ‰) arose there by the action of gold-bearing hydrothermal solutions, the native bismuth has been partly replaced with maldonite. Jonassonite and Pb–Bi sulphosaults (mainly, cosalite Pb₂Bi₂S₅) were formed later in these ores. The overlaying Sb mineralization has given formation not of antimonite (stibnite), but of Pb–Sb sulphosaults (moeloite Pb₆Sb₆S₁₅, etc.), pseudomorphs of chalcostibite after chalcopyrite, as well as aurostibite AuSb₂ after minerals of gold. The replacement of maldonite by aurostibite was resulted in appearance of bismuthate III. The probable replacement reaction is: 2Au₂Bi + 6Sb solv. + + 3Sb₂S₃ solv. → 4AuSb₂ + Bi₂S₃. Bismuthite III (Bi_1.72–1.96Sb_0.29–0.94)₂(S_2.98–3Se_0–0.02)₃, containing 1–7 wt % of Sb, is a product of the maldonite replacement by aurostibite. Moeloite and stibian bismuthate III arose by the Sb mineralization overlaying ores with cosalite. The probable replacement reaction is: 3Pb₂Bi₂S₅ + 3Sb₂S₃ solv. → Pb₆Sb₆S₁₅ + 3Bi₂S₃. Stibian bismuthite-III contains 4–17 wt % of Sb in its composition (Bi_1.36–1.71Sb_0.64–0.29)₂S₃. Appearance of bismuthite with the Sb mineralization where it was developed over ores with native bismuth, maldonite and Pb–Bi sulphosaults is the evidence of key role of the mass action law in mineral-forming processes.

The paper describes Ca-Pb phosphates—pyromorphite and phosphohediphane from the oxidation zone of barite-lead (calcite-barite-galena) ores of the Ushkatyn-III deposit in Central Kazakhstan. Both minerals occur equally frequently within the deposit. Lead phosphates coexist with minerals as almost unaffected by surface changes in ores (galena, pyrite, barite, calcite, rhodochrosite, chamosite, and others), so with minerals of highly oxidized ores (cerussite, montmorillonite, kaolinite, goethite, and others). As the processes of supergene processes develop (during the transition from weakly to strongly oxidized ores), the compositions of newly formed phosphates change regularly in the following consequence: phosphohedifane → rhythmically zonal Ca-Pb phosphate → pyromorphite. At the same time, the habit (and appearance) of mineral crystals changes from dipyramidal-prismatic through elongated prismatic (barrel-shaped) to pinacoidal-prismatic (short-columnar). Crystallization of pyromorphite is possible already at very low concentrations of lead, phosphorus and chlorine in solution. The main source of chlorine is groundwater, and phosphorus is coming from the organic matter of the soil cover overlying ore-bearing deposits. Peculiarities of the chemical composition and crystal structure of Ca-Pb phosphates, as well as the nature of their mineral associations, suggest the presence of a discontinuity in isomorphic miscibility in the series pyrofmorphite–phosphohedifane and phosphohedifane–chlorapatite.

The article provides an empirical method to use the number of violating reflections for the P4/nnc space group to estimate the formation temperature of different polytypes (P4/nnc, P4/n and P4nc) of vesuvianite group minerals. For this purpose, a statistical approach based on an instrumentally investigated 197 samples of vesuvianite group minerals was used. As an example, the results of the study of a number of vesuvianite group samples from skarnoids of the Kovdor alkaline massif are considered. Crystal and chemical limitations of the proposed approach which associate with chemical composition and kinetics of crystallization of vesuvianite group minerals are also discussed.

Objects of the study were colorless single crystals of quartz with a total amount of impurities lesser than 1%. Implantation of vanadium ions into the quartz structure was carried out parallel to the symmetry axis C. Irradiation doses varied from 0.75 × 10¹⁷ to 1.5 × 10¹⁷ ion/cm². With the purpose to anneal radiation defects and to redistribute the implanted vanadium admixture, the post-implanting heat treatment was carried out in the air atmosphere, within the range 200–1000 °C. There was solved issue of ion-beam modification of the colorimetric properties of the quartz matrix with simultaneous control of change in the nature of color of the piezo quartz raw material. In result of the study, samples with annealing temperatures of 383 and 585 °C were investigated most thoroughly by methods of adsorption optical spectroscopy. The quartz sample with annealing temperature 383 °C has acquired an olive-green color due to formation of oxide nanoprecipitates of vanadium ions with different valences: V²⁺, V³⁺, V⁴⁺. The quartz sample with annealing temperature 585 °C become discolored in result of oxidation of vanadium ions and their transition in the pentavalent state V⁵⁺.

The article traces the history of annual reviews of newly discovered minerals published in the magazine Zapiski Rossiiskogo Mineralogicheskogo Obshchestva (Proceedings of the Russian Mineralogical Society), the first experience of their publication, and the further development. The first reviews were published by O.M. Shubnikova, and the very first of them has been written in co-authorship with D.I. Yuferov; it covered the period of time from 1922 through 1932. Later, during the time, reviews were regularly composed and published by E.N. Bonshtedt-Kupletskaya, T.A. Yakovlevskaya, V.I. Kudryashova, and V.N. Smolianinova.