The article presents and analyzes the results of microscopic and microprobe studies of polished sections of the Konder deposit. We have identified ore minerals of the sulfosalt group, and provide data on their chemical composition, spatio-temporal relationships. The joint finding of sulfosalts of lead, silver, antimony, tin, nickel and copper, representing geochemically contrasting groups, allows us to continue the discussion of the history of the formation of the deposit and to clarify some of the features and originality of the named parageneses.

Mineralogical and geochemical studies of the northeastern flank of the Partizanskoe deposit in the zone of its junction with the Dalnegorsk borosilicate deposit revealed Ni–Co arsenide and Ag–Bi telluride mineralization superimposed on typical Pb–Zn ores. The typomorphic features of the arsenides and tellurides, as well as the sequence and physicochemical conditions of their formation, were studied. Rammelsbergite and hessite were found at the deposit for the first time. The authors assume that the arsenide and telluride assemblages formed after the completion of the main skarn–sulfide stage of ore formation. Together with the earlier mineralogical finds of large Bi nuggets and reniform aggregates of native As and Sb in the same junction area, the arsenide–telluride mineralization can be assigned to the geochemically common Ag–Bi–Ni–Co–As (Sb) mineral complex, which in its geochemical features represents in a miniature the ores of hydrothermal five element-type deposits.

Gemological, spectrometric, and chemical properties of alluvial diamonds and their micro inclusions from the Nezametninskaya area, which consider to be diamond-bearing by means of many researchers, were examined. We investigated the sorting of studied diamonds according to their particle size distribution, a complex of the most characteristic typomorphic features, the way the inclusions are located and their contents, ultraviolet microscopy, detection of metal particles on the surface of grains (nickel, cobalt, copper) which are used to provide a greater bond in the manufacture of industrial diamonds. This scientific research has shown us the found minerals have a synthetic origin.

The article presents the results of studying igneous rocks of the Kordonnoye deposit in order to clarify the geodynamic conditions for the formation of the ore-magmatic system (OMS). Based on the study of petrological and geochemical features of igneous rocks and determination of their age, it was concluded that granitoids of the first group (101 ± 2.0–103.5 ± 2.0 Ma), with which tungsten deposits are associated in the region, should be considered as derivatives of the Early Cretaceous complex, the formation which is due to the activity of intracrustal magma chambers producing IS-type melts with limited participation of deep (through-magmatic) fluids. In the schemes of the geodynamic evolution of the region, these rocks correspond to the stage in which the regime of sliding of lithospheric plates dominated. Granites of the second group, with which tin, polymetallic, gold-silver deposits are associated, judging by their age (86.6 ± 1.8–88.3 ± 0.8 Ma) and petrochemical characteristics, represent an association of rocks of the Sikhote-Alin volcanic belt, and belong to the complex of rocks that records subduction mode.

The article reveals the results of the long-term studies for diamond crystals found on the territory of Primorye in placer samples. The crystals’ optical and gemological characteristics, morphology, and the composition of micro inclusions were examined with the microprobe method. Special attention was paid to the study of the photoluminescence spectra of the diamonds, since it is one of the relatively new methods which enables to determine the origin of the diamonds. The rapid development of technologies for the synthetic technical-grade diamonds production has expanded the usage of rough diamonds, including the field of geological exploration. It is widely known that the natural diamonds of technical quality were initially used for making diamond crowns (the end of the XIX century and the beginning of the XX century). Synthetic diamonds are also used to produce crown bits, since the volume of their production is several times higher than the volume of the natural diamonds extraction. The synthetic diamonds properties are similar to those of the natural ones; synthetic diamonds are equal to natural diamonds in abrasive qualities, and the most important thing is that they have a lower processing cost. During the long-term exploitation of drilling crowns, diamond grains may fall out of their seats and be lost. This creates a real risk of natural objects contamination while searching new indigenous diamond deposits. The paper gives an algorithm of research conduction that allows to distinguish between natural and synthetic diamonds, prevent incorrect conclusions and to increase the validity of natural diamond findings in placer deposits.

The Taezhny is a silver with gold (Au : Ag = 1 : 100) vein deposit with a pronounced mineralogical and geochemical selenium ore specialization. The deposit is located in the eastern part of the Sikhote Alin Orogenic Belt, 700 km north of Vladivostok. Similarly to the Mexican Guanajuato deposits typical of the Pacific region, the position of the described ore-bearig area in the region is governed by its relation to an Early Cretaceous island-arc terrane with a distinct geochemical silver enrichment of its folded rock complex. Quartz vein bodies are hosted in the submeridional faults feathering the NE-trending sinistral strike-slip faults. The vein-related alterations are manifested in aureoles of sericitization and silicification of host sandstones. The main silver minerals are freibergite, acanthite, Se-containing pyrargyrite, polybasite, and stephanite. Of the rarer minerals, custelite, electrum, aguilarite, allargentum, and dyscrasite are found. The mineralogical and geochemical zoning of the ore bodies has been revealed, which is emphasized by a highly productive Ag-sulfosalt Se-enriched assemblage in the upper part of the veins and poor ores with predominant acanthite at depth. The veins were formed with the involvement of sodium chloride solutions saturated with CO2 and CH4, in the temperature range from 400 to 150°C. The productive sulfosalt-bearing assemblages were deposited at a sharp pressure decrease due to magmatic-meteoric fluid discharge in zones of solution circulation under the screen of volcanic rocks overlying the Kema Terrane.

From 2009 to 2011, sapphire crystals and corundum- bearing rocks were discovered at Sutara, in the Jewish Autonomous Region of the Russian Far East. These sapphires are typically translucent to semitransparent and blue to pinkish blue. Most of the crystals are heavily included and display prominent growth zoning, twinning planes, and abundant exsolution lamellae. Their primary fluid inclusions contain diaspore crystals and a low-density CO2-CH4 mixture. These inclusions indicate that sapphire mineralization occurred by means of low-density aqueous-carbonic fluids, which were able to carry significant concentrations of alumina. These fluids may have formed as a result of thermal impact of granitic magma on carbonate country rocks. The authors consider Sutara a metamorphic occurrence that formed as a result of diffusive and metasomatic processes at a region of contact between carbonate rocks and pegmatite veins.

В статье изложены результаты исследований гранитоидов одного из объектов Малиновского рудного поля – скарнового шеелит-сульфидного месторождения Кордонное. Магматические породы района месторождения представлены разновозрастными гранитами, которые различаются по петрографическим признакам, по химическому и элементному составу, а также по термобарогеохимическим характеристикам. Обсуждаются критерии рудоносности гранитоидов татибинского комплекса, предполагается их генетическая связь c вольфрамовым (шеелитовым) оруденением в регионе, которая подтверждена сходством характера распределения редкоземельных элементов (РЗЭ) в магматических породах и шеелитах из рудных прожилков и результатами сопоставления термобарогеохимических характеристик рудных растворов и флюидов, сопровождающих формирование гранитов. На основании анализа результатов комплексных исследований сделан вывод о полихронности и полигенности месторождения, обусловленных проявлением двух этапов магматизма и оруденения в процессе формирования рудно-магматической системы (РМС).

The granitoids of the Dal’negorsk borosilicate deposit are ascribed mainly to the high-K metaluminous rocks of the calcic and alkali-calcic series. The thermo-baro-geo-chemical studies showed that they originated from melts with low contents of water (H2O < 3.5% H2O) and CO2 at 800–850°C and 65–90 MPa. The data on the average contents of elements in the rock-forming minerals and the estimated initial water content in the magma point to the absence of a genetic relation between the intrusion and boron mineralization. The granitoid magma was responsible for the skarn formation and for the mobilization and remobilization of boron under a favorable environment. The K/Ar dating (51.0 ± 10 Ma), the geochemical typification (signatures of within-plate, subduction, and collisional granitoids), and the low water content in the parental melts of the granitoids, in accordance with the scheme of the geodynamic evolution of the region, indicate their formation in the lithospheric plate sliding environment.

The results of the study of granitoids from the Kordonnoe scheelite-sulfide skarn deposit in the Malinovka ore field are discussed in this paper. Igneous rocks in the studied area are represented by granites differing in age, which are distinguished in petrography, chemical composition, and thermobarogeochemical characteristics. The genetic relationships of scheelite mineralization to granitoids of the Tatibi Complex are supported by similar REE patterns of granitic rocks and scheelite from ore veinlets and by comparison of thermobarogeochemical characteristics of the ore-bearing solutions and the fluids that accompanied emplacement of granites. Comprehensive investigations have shown that the deposit is multistage and polygenetic. Two stages in the formation of igneous rocks and mineralization are recognized in the evolution of the oremagmatic system.

Any and all proposed theories regarding the origin of sapphires are still very much open to debate. Critical inconsistency arises on the magmatic petrogenesis mechanism of sapphire crystal formation. The Nezantemoye Deposit is one of the most prospective placer deposits of jewelry grade corundum (sapphire) and zircon (jacinth) in Russia, and is known for its native and alluvial gold-wolframite-tin deposits. We present new data obtained from mineral and primary melt inclusions that are syngenetic to corundum. Electron microprobe analysis indicates that rutile, zircon, albite, zinc-bearing hercynite, columbite, and fluorite represent syngenetic mineral inclusions. Silicate melt inclusions are almost always associated with carbon dioxide inclusions; this correlation suggests that a heterogeneous fluid-melt system was present during corundum crystallization. Distinctive features of chemical composition of the inclusions, along with their agpaitic coefficients, indicate that corundum crystallization occurred from granosyenite melts. Primary carbon dioxide-rich inclusions form random groups, or are associated with melt inclusions. P-T conditions for corundum crystallization have been calculated as 780-820 degrees C and 1.7-3 kbar, based on data from primary carbon dioxide and melt inclusions. (C) 2006 Elsevier B.V. All rights reserved.

Data on the petrochemical properties of the granitoids and ores of this deposit were generalized, Rb-Sr-isotopic systems in the granitoids of the Lermontov stock and Shivkin massif and in ore minerals were studied. The sequence of the crystallization of ganitoids and ores and the duration of the development of an ore-magmatic system were determined. The paragenetic relation of magmatic rocks and ores as products of a single magmatic chamber, as well as the role of fluids in the formation of granitoid melts, were outlined.