Volume CLIII, Nº 4 (2024)

The article presents data on the composition and internal structure of cinnabar from sediments of three gold-bearing placers and diluvium of a mercury occurrence in the Middle Urals. Differences in the size and degree of roundness of cinnabar have been established. Cinnabar from Izvyostka River differs from other studied objects in its large grain size (up to 2.5 mm) and high degree of roundness, which indicates the location of the lode source at a short distance. Significant differences were revealed in the set of mineral inclusions in cinnabar. Inclusions of quartz and calcite are widespread. The most contrasting relative to other objects is the association of inclusions in the cinnabar from Izvyostka River. It is distinguished by the wide distribution of rare minerals of the Zn–Hg–Cd–S system, including Cd-rich metacinnabar, Zn-Cd-rich metacinnabar, and Hg-rich sphalerite. Cd-rich metacinnabar with a cadmium content of up to 19.45 wt.% was discovered for the first time. This mineral is close in composition to the synthesized phases (Hg, Cd)S. The totality of data on the inner structure and composition of cinnabar does not allow us to assume the type of the lode sources of most placers. However, typomorphic characteristics and especially the inclusion of rare sulfides Hg, Cd and Zn in cinnabar from sediments of the Izvyostka River indicates the location of a primary source with gold-mercury mineralization near the placer, similar to the Vorontsovskoe gold deposit.

A detailed study of differentiated intrusions of the Misaelga complex located in the Taratash metamorphic block for the first time in the Urals revealed rare-earth mineralization represented by minerals of the chevkinite group. It has been established that during the process of crystallization differentiation at the final stages of the formation of the massif, the alkalinity and alumina content of the last portions of the melt increase, at which the formation of perrierite-(Ce) mineralization becomes possible in the temperature range from ~800 °C to ~1050 °C and partial pressure of oxygen lgfO₂ = –12 .7.

Neyite Ag₂Cu₆Pb₂₅Bi₂₆S₆₈ was identified in the dumps of Yugo-Konevo tungsten deposit (Chelyabinsk oblast, Southern Urals) for a first time in Russia. This rare sulfosalt forms prismatic crystals up to 3 х 0.5 mm in fluorite-muscovite-quartz veins and is associated with aikinite, tetradymite and pyrite. Reflectance spectra and values of neyite are published for the first time. The chemical composition of neyite is (wt. %, electron microprobe, mean of 7 analyses): Ag 1.75, Cu 3.59, Pb 35.01, Cd 0.12, Bi 42.59, S16.54, total 99.60. The empirical formula calculated based on S = 68 atoms per formula unit is Ag_2.14Cu_7.45Pb_22.27Cd_0.14Bi_26.86S₆₈. The crystal structure of neyite from Yugo-Konevo was refined on the single crystal, R₁ = 3.43 %, wR₂ = 7.22 %. The mineral is monoclinic, space group С2/m, a = 37.3900(6) Å, b = 4.05500(10), c = 43.5821(7) Å, β = 108.740(2)°, V = 6257.5(2) ų, Z = 2. The structure of neyite is based upon three different modules of archetypal PbS structure: (111)_PbS slabs of octahedra extended along b alternate with (100)_PbS slabs in a direction. Resulting layers are alternated with (922) _PbS layers along c. The main structural feature of neyite from Yugo-Konevo deposit that distinguishes it from previously published data on neyite from type locality and cuproneyite is the disorder of Me16 site and the presence of the additional Cu5 site. These features, combined with the bond valence sums analysis, suggest the presence of chains of CuS₄ tetrahedra alternating with chains of BiS₆ octahedra.

Comparison of the Raman characteristics of six mineral species (burbankite, calcioburbankite, hanneschite, remondite-(Ce), petersenite-(Ce), and sanromanite) of the burbankite group revealed differences in the band positions of fully symmetric valence vibrations ν₁ related to normal vibrations of the (CO₃)^2– anion group. Significant variations in band widths were also identified for ν₁ vibrations. The observed differences in the Raman spectra of burbankite group minerals depend on the chemical composition of the studied samples. Additional photoluminescence bands found in some spectra are shown to be a direct indication of significant content of rare earth elements in the samples. Raman study of sanromanite has been carried out for the first time.

The article is dedicated to the 250th anniversary of the first discovery of cobalt mineralization in Russia – the mineral erythrin (Co₃[AsO₄]₂ 8H₂O). The find was made by Bergmaster of the Berg-Collegium A.M. Karamyshev in 1774 on the silver ore vein in the Roymensky navolok, during the scientific search and exploration expedition of 1773–1774, organized by the Berg-Collegium to Russian Lapland. The article, based on archival and published sources, traces the events that prompted the Berg-Collegium to attempt to revive silver mining on the Medvezhiy Island and the Kandalaksha coast of Russian Lapland. The history of organization and conduct in 1773–1774 has been reconstructed scientific search and exploration expedition of the Berg-Collegium to silver mining sites in Russian Lapland during the reign of Anna Ioannovna. It is shown that A.M. Karamyshev is the first discoverer of cobalt mineralization in Russia.

The book by G. A. Yurgenson “Emerald, aquamarine, heliodor…” devotes to the popular scientific description of crystal forms, composition and structure, the history of knowledge and use of precious varieties of beryl. It examines the nature of their colour, formation conditions, and the most important deposits. The original information obtained by the author about beryl deposits in Russia and Afghanistan is included. The book is illustrated with photographs of beryl samples stored in the world’s greatest museums. The book is definitely an important contribution to the knowledge of beryl and can be recommended both to geologists and gemologists, and to a amateur mineralogists.