Optical Microprobe Research Articles

An archaeometric approach of historical mortars taken from Foligno City (Umbria, Italy): news insight of Roman Empire in Italy

This research has been focused on the study of mortars from four bridges of the ancient city of Foligno (Umbria, Italy), located along the old path of the Topino-Tinia River. An archaeometric study was undertaken to analyse ten archaeological samples in order to define textural features, chemical composition and raw materials used for their production. For this purpose, different analytical methods were used, such as polarising optical microscope (POM), X-ray diffraction (XRD) and electron microprobe analysis coupled with energy-dispersive spectrometry (EMPA-EDS).

Dual-core all-fiber integrated immunosensor for detection of protein antigens

An optical fiber interferometric microprobe for detection of specific proteins is presented in this paper. The microprobe is an all-fiber device, which is based on Michelson interferometer configuration, which allows for detection of protein antigens in an analyzed solution thanks to antibodies immobilized on the sensor surface. The interferometer is made of dual core fiber and has a precisely formed arm length difference, achieved by splicing a fragment of polarization maintaining fiber to one of the cores. An all-fiber configuration of the sensor decreases substantially cross-sensitivities to temperature and deformation in comparison to other optical fiber interferometers. Reported sensor has a sensing region on the tip of the interferometer and therefore may be used for point measurements in medicine. The immunosensor and optical measuring system are designed to utilize the most common broadband light sources that operate at a central wavelength of 1.55 µm. The results show that it is possible to detect a protein antigen present in a solution by using an all-fiber interferometer coated with specific antibodies. The resulting peak shift can reaches 0.6 nm, which is sufficient to be measured by an optical spectrum analyzer or a spectrometer. A model allowing for estimation of the value of lower limit of detection for such sensors has been elaborated. The elaborated detection system may act as a framework for detection of various antigens and thus it can find future applications in medical diagnostics.

Immobilized optical fiber microprobe for selective and sensitive Escherichia coli detection.

Escherichia coli (E. coli) bacteria have been found to be responsible for various health outbreaks caused by contaminated food and water. Accurate and rapid test of E. coli is thus crucial for protecting the public health. A fast-response, label-free bacteriophage-based detection of E. coli using multimode microfiber probe is proposed and demonstrated in this paper. Due to the abrupt taper and subwavelength diameter, different modes are excited and guided in the microfiber as evanescent field that can interact with surrounding E. coli directly. The change of E. coli concentration and corresponding binding of E. coli bacteria on microfiber surface will lead to the shift of optical spectrum, which can be exploited for the application of biosensing. The proposed method is capable of reliable detection of E. coli concentration as low as 103 cfu/mL within the range of 103 to 107 cfu/mL. Owing to the advantages of high sensitivity and fast response, the microfiber probe has great potential application in the fields of environment monitoring and food safety.

Influence of the aligned flow obstacles on critical heat flux in two-phase boundary layer flow under a low flow condition

In the EU-APR1400, an ex-vessel core catcher system, a key design component of considerable interest is the engineered corium cooling system. It consists of a cooling channel in which many short columnar structures called studs are placed to support the static and dynamic loads on the core catcher body and to provide the coolant flow path underneath the core catcher body. This study investigated the effect of aligned obstacles on the inclined downward facing critical heat flux (CHF) under a low flow condition using a high-speed camera and an optical fiber microprobe measuring the local void fraction. A laboratory-scale experimental apparatus for a prototypical core catcher system was built, and experiments were conducted with various mass fluxes and obstacle shapes under atmospheric pressure. Results showed a linear proportional relation between the inlet mass flux and corresponding CHF with the existence of a transition flow rate, beyond which the proportionality becomes double. It was also confirmed that the aligned flow obstacles had a positive effect on the CHF under a relatively high mass flux, but a negative effect appeared in the pool boiling condition. Computational fluid dynamics helped in the understanding of key physical mechanisms through which the obstacles affect the CHF, on the basis of the experimental results.

Spectroscopy and DFT studies of uranyl carbonate, rutherfordine, UO2CO3: a model for uranium transport, carbon dioxide sequestration, and seawater species

Several optical microprobe experiments of the anhydrous uranium carbonate—rutherfordine—are presented in this work and compared to periodic density functional theory results. Rutherfordine is the simplest uranyl carbonate and constitutes an ideal model system for the study of the rich uranium carbonate family relevant for environmental sustainability. Micro-Raman, micro-reflectance, and micro-photoluminescence (PL) spectroscopy studies have been carried out in situ on native, micrometer-sized crystals. The sensitivity of these techniques is sufficient to analyze minute amounts of samples in natural environments without using x-ray analysis. In addition, very intense micro-PL and micro-reflectance spectra that were not reported before add new results on the ground and excited states of this mineral. The optical gap value determined experimentally is found at about 2.6–2.8 eV. Optimized geometry, band structure, and phonon spectra have been calculated. The main vibrational lines are identified and predicted by this theoretical study. This work is pertinent for optical spectroscopy, for identification of uranyl species in various environmental settings, and for nuclear forensic analysis.

Immobilized optical fiber microprobe for selective and high sensitive glucose detection

Abstract Optical fiber microprobe functionalized with Glucose oxidase (GOD) has been proposed for bio-selective and high-sensitive glucose detection. Taking advantages of the free amine groups of 3-aminopropyl- triethoxysilane (APTES), the enzymes (GOD) are immobilized on the multimode microfiber through covalent interaction. Surface characterization offered by optical microscopy, scanning electron microscope and multiphoton laser scanning microscopy provide detailed evidences about the effect of the bio-functionalization. The fabricated microfiber sensor is immersed into glucose solutions at different concentrations to record and analyze the transmission spectrums from an optical sensing interrogator. The experimental results demonstrate that the resonant wavelength shift is linearly correlated with the glucose concentration in the range of 0–3.0 mg/ml with a response coefficient of 1.74 nm/mg −1 ml −1 . Meanwhile, the reported sensor is also proved to be of practical utility by accurately detecting glucose content in animal serum samples. Due to the small size, label-free sensing capacity and excellent practicality, the proposed device has great potential to be applied in the fields like disease diagnosis, clinical analysis and food safety.

PHOSPHORUS ZONING FROM SECONDARY OLIVINE IN MANTLE XENOLITH FROM MIDDLE ATLAS MOUNTAINS (MOROCCO, AFRICA): IMPLICATIONS FOR CRYSTAL GROWTH KINETICS

Mantle xenolith samples in contact with basalt flows were collected from the Tafraoute maar in Morocco. Discrete melt veins are present in one xenolith sample, crosscutting primary layering and foliation. We used both optical microscopy and electron microprobe analysis to characterize the glasses and minerals in the melt veins. The melt veins consist of glass and crystals of olivine, clinopyroxene, plagioclase, spinel and apatite. The olivine in the melt veins is quite distinct from the same mineral within the matrix due to its characteristic P-enriched rims (up to 0.3 wt.%). Correlations between Al and P, as well as experimentally determined partition coefficient for P, point towards non-equilibrium partitioning during rapid crystal growth at the end of crystallization.

The Role of Case Hardening in the Preservation of the Cavates and Petroglyphs of Bandelier

ABSTRACTBandelier National Monument (BNM) was created to protect an extraordinary inventory of archaeological resources carved in the Tshirege Member of the Bandelier Tuff. These include more than one thousand excavated chambers, called cavates, used for dwelling, storage, and textile production. The glass-rich tuffs at the base of the Tshirege Member are poorly consolidated and susceptible to erosion by wind, rain, and mechanical abrasion, with resultant loss of cultural material. However, rock surfaces develop protective weathering rinds that are resistant to erosion. Using optical microscopy, SEM-EDS, XRD, and electron microprobe analysis, we determined that this rind consists of clay and silt sediments colonized by lichens and other surface biota, accompanied by the precipitation of secondary minerals in the near-surface pore space. Scoping experiments focused on glass-organic acid interactions indicate that oxalic acid excreted by microbial crust constituents catalyzes biogeochemical reactions that lead to the preferential dissolution of Si, Al, and Fe components of the volcanic glass; these cations become available for precipitation of opal, and smectite and sepiolite clays. Enzyme assays that quantify biological activity at outcrop surfaces indicate that microbial populations initially thrive as they derive nutrients from the dissolution reactions of the glass, but activity starts to decline as precipitation of secondary minerals limits access to new sources of nutrients, so that alteration processes are self-limiting. As case hardening progresses, imbibition rates at the surface decrease, and the erosion resistance of the altered surfaces is substantially improved. This article presents summary results of research conducted over a period of five years to characterize the roles of lichens and other microflora in rind formation, and the resulting contributions to tuff stability. The interaction of lichens and other microflora with rock surfaces in archaeological sites and monuments is usually explored in terms of biodeterioration and consequent damage. However, this study shows that, under some circumstances, lichens and microflora provide a level of erosion protection to relatively porous and unconsolidated rock strata that outweighs their biodeteriorative effects.

Size-dependent kinetics of reactive diffusion in nano-grained Ag-Sn thin films

The kinetics of lateral Ag3Sn intermetallic phase propagation during Sn diffusion into nano-grained Ag films has been studied by optical microscopy, SEM and electron microprobe in a temperature range 140 – –200°C. The Sn and Ag films of various thicknesses were deposited onto glass substrate with small overlap (5–10μm). It was detected that the rates of Ag3Sn propagation in thin film couples exceed more than two orders of magnitude the propagation rate in a bulk of massive Ag-Sn samples. Kinetics of the phase propagation depends on the grain size in Ag-film: the smaller grain size, the faster is the propagation rate. The mechanism of phase propagation is proposed in assumption that the kinetics is controlled by grain boundary (GB) diffusion through the intermetallic layer with subsequent chemical reaction between Ag and Sn atoms at the Ag3Sn -Ag interface. By comparison of experimental data on Ag3Sn propagation with the proposed theory the Arrhenius equation Diδ=8.1×10-14exp-55.4kJ/molRTm3/s was obtained for products Di δ (Di is the GB diffusion coefficient of Sn in the Ag3Sn phase, δ is the GB width).

Low-Temperature Formation of Sn-Doped Ge on Insulating Substrates by Metal-Induced Crystallization

Low-temperature formation of Sn-doped Ge on insulator is desired to realize next generation flexible electronics. To achieve this, metal-induced crystallization (MIC) of a-GeSn is investigated. By MIC of a-GeSn with initial Sn concentration of 5%, Sn-doped Ge is obtained at low temperatures (<250℃). The Sn concentration (0.5-2.0%) in the grown layers can be controlled by modulating the annealing temperatures in the range of 150-250℃. Introduction A technique for low-temperature (≤250°C) formation of high-quality crystalline Ge films on insulator is expected to realize advanced high performance thin film transistors (TFT) on flexible plastic substrates (softening temperature: ~300oC). To improve quality of Ge crystals, Sn-doping (<4%) is very effective, because it enables passivation of point defects in Ge [1]. This triggered the recent research of solid-phase crystallization of Sn-doped Ge (Sn concentration: 2%) on SiO2layers [2]. However, the growth temperature (425°C) reported to date is higher than the softening temperatures of plastic substrates. To decrease the growth temperature of Sn-doped Ge, in the present study, we investigate metal-induced crystallization (MIC) of a-GeSn. This successfully decreases the growth temperature below 250°C. Experimental Procedure Fig.1 schematically shows the procedure of sample preparation. Amorphous Ge1-xSnx layers (x: 0-0.2, thickness: 100 nm) were deposited on quartz substrates at room temperature. Then, Au layer patterns were formed on the amorphous GeSn layers. The samples were annealed at 150-250oC for 10-60 min to induce lateral growth in a N2ambient. The growth characteristics were analyzed by Nomarski optical microscopy and microprobe Raman spectroscopy. Results and Discussion Figs. 2(a) and 2(b) show Nomarski optical micrographs of Ge1-xSnx (x: 0.05 and 0.2, respectively) samples after annealing at 250oC for 10 min. Au pattern regions are located in the left side areas of the micrographs. In the case of the low Sn concentration (5%), different contrast regions are observed around the Au patterns, as indicated by the broken lines. On the other hand, the sample with the high Sn concentration (20%) shows no change around the Au pattern after annealing. The Raman spectra obtained from these samples are summarized in Fig. 2(c). In Raman spectra #1 for the low Sn concentration (5%), a sharp peak due to Ge-Ge bonding in c-Ge is clearly observed. On the other hand, no peaks are detected in spectra #3 for the sample with the high Sn concentration (20%). These results indicate that lateral growth is generated from the Au patterns for samples with the low Sn concentration (5%), while it is not generated for the high Sn concentration (20%).The lateral growth lengths at 150 and 250oC for samples with various Sn concentrations were estimated using theNomarski optical microscopy combined with line-scanning of microprobe Raman measurements. The results are summarized as a function of the annealing time in Fig. 3. In the case of low Sn concentrations (<5%), lateral growth lengths increase in a short annealing time (10 min). In addition, the growth lengths increase with increasing annealing temperature and exceed 20 μm at 250°C, which is sufficient for device fabrication.The substitutional Sn concentrations in grown layers for samples with the initial Sn concentration of 5% are evaluated by peak shift of Raman spectra. Substitutional Sn concentrations of 0.5−2.0% are obtained in grown layers, which is useful to passivate point defects in Ge [1]. The substitutional Sn concentration depended on the annealing temperature. This indicates that the substitutional Sn concentration can be controlled by modulating annealing temperature. This technique will be useful to realize next generation flexible electronics.

Raman and optical spectroscopic investigation of gem-quality smoky quartz crystals

Rough samples and cut stones of smoky quartz from the Slovak Ore Mts. and the Tribeč Mts. were investigated by Raman and optical spectroscopy, electron microprobe and standard gemological techniques. Raman spectra of both cut stones and polished slices comply with already published data on quartz with the most prominent bands at around 463, 205 and 128cm−1. The samples contain two-phase H2O-CO2 fluid inclusions aligned in crystallographically defined planes and also freely scattered. Optical spectra showed high absorption at violet-to-green region on [AlO4]4− group color centers and perceived brown color results from strong green-to-orange transmission with addition of red. Exposition time to natural irradiation also influences the color tone, hue and saturation. Gemological research on this material has confirmed that it is very suitable for jewelry. Our applied methodology and results documents advantages of Raman and optical spectroscopy in the research of smoky quartz as a gemstone.

Fungal Ferromanganese Mineralisation in Cretaceous Dinosaur Bones from the Gobi Desert, Mongolia

Well-preserved mycelia of fungal- or saprolegnia-like biota mineralised by ferromanganese oxides were found for the first time in long bones of Late Cretaceous dinosaurs from the Gobi Desert (Nemegt Valley, Mongolia). The mycelia formed a biofilm on the wall of the bone marrow cavity and penetrated the osteon channels of the nearby bone tissue. Optical microscopy, Raman, SEM/EDS, SEM/BSE, electron microprobe and cathodoluminescence analyses revealed that the mineralisation of the mycelia proceeded in two stages. The first stage was early post-mortem mineralisation of the hyphae by Fe/Mn-oxide coatings and microconcretions. Probably this proceeded in a mildly acidic to circumneutral environment, predominantly due to heterotrophic bacteria degrading the mycelial necromass and liberating Fe and Mn sorbed by the mycelia during its lifetime. The second stage of mineralisation, which proceeded much later following the final burial of the bones in an alkaline environment, resulted from the massive precipitation of calcite and occasionally barite on the iron/manganese-oxide-coated mycelia. The mineral phases produced by fungal biofilms colonising the interiors of decaying dinosaur bones not only enhance the preservation (fossilisation) of fungal remains but can also be used as indicators of the geochemistry of the dinosaur burial sites.

The influence of structural heterogeneity of hollow glass microspheres on physical and chemical processes of the formation of materials and coatings

The physical and chemical processes of formation of new compositions based on hollow glass microspheres are discussed in the article. The aim – to determine the influence of the structural heterogeneity of hollow glass microspheres of sodium silicate composition on the physical and chemical processes of formation of hot aluminum-matrix materials and coatings based on electric-Sv-AMg5 and Sv-08G2S. Researches are performed by electronic and optical microscopy, X-ray diffraction and electron microprobe analysis. The basis of the laws of formation of the new-metal materials and coatings based on new knowledge about the mechanisms of formation of a liquid phase based on the structural heterogeneity of hollow glass microspheres that can predict the physical and chemical processes at the metal – glass boundary surface. The theoretical researches allow us to establish the distinctive features of the structure formation depending on the method of preparing the compositions, and are aimed at improving their competitiveness. The results are used to predict the mechanical properties of the x-ray and metal-glass materials and coatings for their further use for the manufacture of structures of biological protection of ships and floating structures, for the transportation and storage of radioactive substances.

Compatibility between the Molten Mg-25Al-15Zn-14Cu Alloy and Stainless Steel for Phase-Transformation Thermal Storage Facility

The compatibility of molten Mg-25Al-15Zn-14Cu alloy with several candidate vessel shell materials such as 304 stainless steel, 201 stainless steel for phase-transformation thermal storage facility were evaluated by means of immersion corrosion test at 500°C for 1000 h. The microstructure, element distribution and surface corrosion layer structure and phase composition of the cross section of corrosion samples were analyzed by using optical microscope (OM), X-ray diffraction (XRD) and electron microprobe analysis (EPMA). The results show that two kinds of stainless steel have good compatibility in the molten Mg-25Al-15Zn-14Cu alloy. The thickness of the erosion layer is less than 0.1mm. The corrosion interface of corrosive material in the molten Mg-25Al-15Zn-14Cu alloy can be divided into the base layer, the diffusion layer, the corrosion layer, segregation layer (C, Cr, Ni), linked coating layer.

Changes to the Marine Geology Editorial Team in 2015

The microstructures, mineralogy and chemistry of four representative samples collected from cores extracted from the Japan Trench during Integrated Ocean Drilling Project Expedition 343, the Japan Trench Fast Drilling Project (JFAST) have been studied using optical microscopy, TEM, SEM, XRF, XRD and microprobe analyses. The samples provide a transect from relatively undeformed marine sediments in the hanging wall, to the undeformed footwall material, crossing the thrust interface between the Pacific and North American plate, where the fault slipped during the March 2011 Tohoku-Oki earthquake. Our preliminary results suggest that the low strength of JFAST fault gouge material is caused by the high amount of clay minerals (~ 60% smectite, ~ 14 illite). Clay minerals in the décollement (gouge) sample are partly replaced by newly formed manganese oxide, which precipitated from hydrothermal fluids. Dauphine twins were found in quartz grains of the décollement sample suggesting local high stress possible during seismic loading. Other microstructures cannot be assigned unambiguously to co-seismic or a-seismic faulting processes. The observed scaly clay fabric is consistent with observations in many other plate-boundary fault zones. Significant grain size reduction was found in the fault (décollement) zone sample. But a change in lithology of the fault material cannot be ruled out. Microstructures typical for a-seismic deformation like dissolution–precipitation features (e.g. dissolved grain boundaries, mineral alteration) occur in all JFAST core samples, but more frequently in the décollement sample.

Dual-Material Electron Beam Selective Melting: Hardware Development and Validation Studies

ABSTRACT Electron beam selective melting (EBSM) is an additive manufacturing technique that directly fabricates three-dimensional parts in a layerwise fashion by using an electron beam to scan and melt metal powder. In recent years, EBSM has been successfully used in the additive manufacturing of a variety of materials. Previous research focused on the EBSM process of a single material. In this study, a novel EBSM process capable of building a gradient structure with dual metal materials was developed, and a powder-supplying method based on vibration was put forward. Two different powders can be supplied individually and then mixed. Two materials were used in this study: Ti6Al4V powder and Ti47Al2Cr2Nb powder. Ti6Al4V has excellent strength and plasticity at room temperature, while Ti47Al2Cr2Nb has excellent performance at high temperature, but is very brittle. A Ti6Al4V/Ti47Al2Cr2Nb gradient material was successfully fabricated by the developed system. The microstructures and chemical compositions were characterized by optical microscopy, scanning microscopy, and electron microprobe analysis. Results showed that the interface thickness was about 300 μm. The interface was free of cracks, and the chemical compositions exhibited a staircase-like change within the interface.

Co-seismic and/or a-seismic microstructures of JFAST 343 core samples from the Japan Trench

Abstract The microstructures, mineralogy and chemistry of four representative samples collected from cores extracted from the Japan Trench during Integrated Ocean Drilling Project Expedition 343, the Japan Trench Fast Drilling Project (JFAST) have been studied using optical microscopy, TEM, SEM, XRF, XRD and microprobe analyses. The samples provide a transect from relatively undeformed marine sediments in the hanging wall, to the undeformed footwall material, crossing the thrust interface between the Pacific and North American plate, where the fault slipped during the March 2011 Tohoku-Oki earthquake. Our preliminary results suggest that the low strength of JFAST fault gouge material is caused by the high amount of clay minerals (~ 60% smectite, ~ 14 illite). Clay minerals in the decollement (gouge) sample are partly replaced by newly formed manganese oxide, which precipitated from hydrothermal fluids. Dauphine twins were found in quartz grains of the decollement sample suggesting local high stress possible during seismic loading. Other microstructures cannot be assigned unambiguously to co-seismic or a-seismic faulting processes. The observed scaly clay fabric is consistent with observations in many other plate-boundary fault zones. Significant grain size reduction was found in the fault (decollement) zone sample. But a change in lithology of the fault material cannot be ruled out. Microstructures typical for a-seismic deformation like dissolution–precipitation features (e.g. dissolved grain boundaries, mineral alteration) occur in all JFAST core samples, but more frequently in the decollement sample.

Melting, fluid migration and fluid-rock interactions in the lower crust beneath the Bakony-Balaton Highland volcanic field: a silicate melt and fluid inclusion study

Plio-Pleistocene alkali basalt hosted mafic garnet granulite xenoliths were studied from the Bakony-Balaton Highland Volcanic Field (BBHVF) to trace fluid-melt-rock interactions in the lower crust. Two unique mafic garnet granulite samples were selected for analyses (optical microscopy, microthermometry, electron microprobe, Raman and IR spectroscopy), which contain a clinopyroxene-plagioclase vein and patches with primary silicate melt inclusions (SMI). The samples have non-equilibrium microtexture in contrast with the overwhelming majority of previously studied mafic garnet granulite xenoliths. Primary silicate-melt inclusions were observed in plagioclase, clinopyroxene and ilmenite in both xenoliths. The SMI-bearing minerals located randomly in Mi26 and in a clinopyroxene-plagioclase vein on the edge of Sab38 granulites. Petrography and the fluid and melt inclusion study suggest that at least three fluid events occurred in the deep crust represented by these xenoliths. 1. Primary CO2-dominated ± CO ± H2S fluid inclusions were observed in the wall-rock part of Sab38 xenolith. 2. The crystallization of new clinopyroxene from melt, with CO2 + H2O fluid. 3. The crystallization of new plagioclase occurred in a heterogeneous fluid-melt system with additional N2 and CH4 during crystallization. A local reaction was observed between sphene and acidic melt, which formed ilmenite + clinopyroxene + plagioclase ± orthopyroxene. The ‘water’ content of the rock forming minerals was determined by infrared spectroscopy. The calculated bulk ‘water’ content of the Mi26 xenolith is 171 ± 51 ppm wt. %. The bulk wall rock part of the Sab38 granulite contains 55 ± 17 ppm wt. % of ‘water’, whereas the bulk plagioclase-clinopyroxene vein contains 278 ± 83 ppm wt. %. These results imply a very dry lower crust, locally hydrated by percolating fluids and melts.

Miniature silicon Michelson interferometer characterization for dimensional metrology

Dimensional metrology applications require performing measurements of profile and form/shape of parts at a nanometer-level of accuracy. Therefore, the metrological characteristics of a miniature optical micro-probe based on a Michelson interferometer are evaluated. The optical micro-probe is designed to perform dimensional measurements with a target uncertainty in the order of few nanometers. Two micro-probe designs having reflection-transmission ratios of 75–25% and 25–75%, are characterized. Two optical setups have been implemented as well: firstly, using a single laser diode with a 1550.3nm wavelength and secondly using a tunable laser source in the C-L bands. The characterization of the two micro-probes is performed using a new ultra-precise test bench, with respect to both dissociated metrology structure and Abbe principles. The experiments allow the evaluation of the error sources such as: stability, axial motion errors (residual errors), material dependence, tilt angle and roughness of the tested object. The experimental results revealed that dimensional measurements could be achieved with nanometer-scale errors, ranging from 2nm to 15nm, depending on the probe design and the reflectance of the device under test.

Mineralogy of Early Cambrian Ni‐Mo Polymetallic Black Shale at the Sancha Deposit, South China: Implications for Ore Genesis

AbstractThe mineralogy of the Early Cambrian Ni–Mo polymetallic black shale ores at the Sancha deposit, South China, was investigated to better the understanding of the complex ore genesis by optical microscope, electron microprobe, and scanning electron microscope. Analytical results show that the sulfides in the ore bed mainly comprise C/MoS2 mixed‐layer phase (MoSC), millerite, and pyrite. Of these, MoSC and millerite are the main ore minerals of Mo and Ni, respectively. Pyrite is subdivided into six types based on its morphology, occurrence, relationship to Ni‐ and Mo‐bearing minerals, and chemical composition. Many millerite crystals cut early‐formed MoSC, implying that these two minerals formed at different stages. The concentrations of biogenic elements (e.g., Sb) in the MoSC are high compared with those in millerite, implying a close relationship between MoSC and organic matter. These data provide a new and improved understanding of the complex ore genesis at the Sancha deposit, and can be applied to other black‐shale‐hosted mineral deposits worldwide.