Synthetic Minerals Research Articles

Reductive Dechlorination of Trichloroethylene (TCE) in Competition with Fe and Mn Oxides—Observed Dynamics in H2-dependent Terminal Electron Accepting Processes

The determination of hydrogen (H2) concentration together with the products of microbial reduction reactions in a trichloroethylene dechlorinating system is conducted to delineate the ongoing predominant terminal electron accepting processes (TEAP). Formate was used as electron donor and synthetic Fe minerals or environmental samples were used as the substrate. Iron(III) and Mn(IV) reduction limited microbial dechlorination by the mixed anaerobic culture by decreasing the level of H2 in the system. The H2 measurements indicated that the H2 concentration at which different TEAPs occur can overlap and thus these TEAPs can therefore occur concurrently rather than exclusively. Difference in Fe(III) bioavailability and hence, Fe(III) reduction partially explain this wide range. The distinction between dechlorination and other microbial reduction processes based on H2 threshold values is not feasible under such conditions, though there appears to be a relation between the rates of H2 consuming process and the observed H2 level.

ChemInform Abstract: Biomedical Applications of Cationic Clay Minerals

AbstractReview: 172 refs.

Boron isotopic fractionation in aqueous boric acid solutions over synthetic minerals: Effect of layer and surface charge on fractionation factor

Boron isotopic fractionation in boric acid solutions during adsorption on synthetic manganese oxides (birnessite “B” and cryptomelane “C”) and Mg–Al-layered double hydroxide “LDH” was investigated. The materials were characterized by elemental analyses, powder X-ray diffraction, FTIR spectra, BET surface area and zeta potential measurements. Batch experiments were conducted without changing the solution pH to correlate the boron sorption properties of the adsorbents with isotopic fractionation in the associated boric acid solutions. The results showed that boron isotopic composition of the contact solution is heavily dependent on the selective adsorption of B(OH)3 or B(OH)4− species due to the charge properties of the minerals. With B and C, possessing negatively charged surfaces, 10B(OH)4− was preferentially fractionated in the solution due to the transfer of the Lewis acidic 11B(OH)3 species while with LDH selective adsoption of 10B(OH)4− by positive layers was favorable resulting in the enrichment of the heavier isotope in the solution.

熱電変換材料として魅力的な人工硫化銅鉱物とそれを用いた発電モジュールの開発

熱電変換材料として魅力的な人工硫化銅鉱物とそれを用いた発電モジュールの開発

Raman spectroscopy characterisation of synthetic platinum-group minerals (PGM) in the Pd–Sn–Te and Pd–Pb–Te ternary systems

The identification of minerals that occur as tiny and rare phases such as most of the natural platinum-group minerals (PGM) is a challenging target. The main reason for that resides in their size (generally less than 10 micrometres) and mode of occurrence ( i.e. polyphasic aggregates) that make problematic the identification by standard X-ray diffraction methods. In this contribution we have applied the Raman spectroscopy to synthetic PGM in the ternary systems Pd–Sn–Te and Pd–Pb–Te. Some of the analyzed PGM show characteristic Raman bands and the following PGM can be distinguished using the Raman spectroscopy: merenskyite, kotulskite, kojonenite, pasavaite and Pd 3 Te 2 . Other PGM in the ternary Pd–Sn–Te and Pd–Pb–Te systems cannot be identified using this technique. These results demonstrate that Raman spectroscopy can be considered as an innovative and complementary methodology with a potential to identify and to better characterize the PGM.

Characterization of porosity in sulfide ore minerals: A USANS/SANS study

Porosity plays a key role in the formation and alteration of sulfide ore minerals, yet our knowledge of the nature and formation of the residual pores is very limited. Herein, we report the application of ultra-small-angle neutron scattering and small-angle neutron scattering (USANS/SANS) to assess the porosity in five natural sulfide minerals (violarite, marcasite, pyrite, chalcopyrite, and bornite) possibly formed by hydrothermal mineral replacement reactions and two synthetic sulfide minerals (violarite and marcasite) prepared experimentally by mimicking natural hydrothermal conditions. USANS/ SANS data showed very different pore size distributions for these minerals. Natural violarite and marcasite tend to possess less pores in the small size range (<100 nm) compared with their synthetic counterparts. This phenomenon is consistent with a higher degree of pore healing or diagenetic compaction experienced by the natural violarite and marcasite. Surprisingly, nanometer-sized (<20 nm) pores were revealed for a natural pyrite cube from La Rioga, Spain, and the sample has a pore volume fraction of ~7.7%. Both chalcopyrite and bornite from the massive sulfide assemblage of the Olympic Dam deposit in Roxby Downs, South Australia, were found to be porous with a similar pore volume fraction (~15%), but chalcopyrite tends to have a higher proportion of nanometer-size pores centered at ~4 nm while bornite tends to have a broader pore size distribution. The specific surface area is generally low for these minerals ranging from 0.94 to 6.28 m2/g, and the surfaces are generally rough as surface fractal behavior was observed for all these minerals. This investigation has demonstrated that USANS/SANS is a very useful tool for analyzing porosity in ore minerals. We believe that with this quantified porosity information a deeper understanding of the complex fluid flow behavior within the porous minerals can be expected.

Photoluminescent europium(III) complex intercalated in natural and synthetic clay minerals for enhanced latent fingerprint detection

Fluorescent nanohybrid materials, europium(III) complex intercalated Na+-smectite clay minerals (synthetic hectorite and natural montmorillonite), have been developed to visualize latent fingerprints. The guest europium(III) complex ([EuCl2(Phen)2(H2O)2]Cl·H2O) was obtained by simple complex reaction between europium chloride hexahydrate (EuCl3·6H2O) and 1,10-phenanthroline (Phen) as a 1:2 molar ratio of Eu3+ ion to ligand molecules. The intercalated nanohybrids ([Eu(Phen)2]3+-clay minerals) were obtained through ion exchange reaction of interlayer sodium cation with europium complex ion. Guest europium(III) complex and [Eu(Phen)2]3+-clay mineral hybrids were characterized by powder X-ray diffraction, Fourier transform infrared, thermogravimetry-differential thermal analysis (TG-DTA), elemental analysis, UV–visible and fluorescence spectroscopy. The intercalated complex maintains a characteristic red 5D0–7F2 emission at wavelength 617nm, which is comparable to that of the free complex. The 5D0–7F2 emission intensity of [Eu(Phen)2]3+-laponite was ca. 3.5 times higher than that of [Eu(Phen)2]3+-montmorillonite, due to the presence of quenching impurities in natural montmorillonite itself. Fingerprint residues on glass slides were harvested by using [Eu(Phen)2]3+-clay mineral powders, resulting in good definition for enhanced latent fingerprint detection. Particularly, [Eu(Phen)2]3+-hectorite hybrid powder was more clearly separated from the background compared to the montmorillonite hybrid powder.

Mineral Analyses &amp; Implications on the Dispersion of Bismuth in the Supergene Environment of Eastern Australia

In the Australian context, bismuth minerals are important constituents, associated with Mo, W and Sn, of highly acidic and very rich, low tonnage, deposits of the eastern ranges of Australia. Bi has been used extensively as a pathfinder element in geochemical exploration for a variety of such deposits and others and therefore it is important to understand its behaviour[1-3]. The behaviour of Bi has been described in the terms of its solution speciation as a function of pH which is well-established [4-7]and provides a first order, but simplistic, assessment of its mobility in pore solution in the regolith. Recent reviews have highlighted a lack of understanding in regards to bismuth in oxidising environments. Bismuth is estimated to have an average crustal abundance of 48 ppb [8], but is highly fractionated across different rock types and sediments with reported concentrations from 30 ppb to greater than 20 ppm an average Bi concentration in soils of 0.2 ppm but this is difficult to reconcile with the data mentioned above. A review of bismuth values [9] concluded similar concerns and further highlighted that a background ground water concentration could not be honestly concluded especially in uncontaminated environments. This is due to no independent focused study on Bi concentrations in the environment and that other factors such as sampling, testing methods and protocols were not consistent. To draw any conclusion on bismuth values, a proper understanding of the dispersion of Bi in oxidising environments must be made. This requires understanding of its low temperature aqueous chemistry and knowledge of the secondary Bi minerals that serve to buffer the element between the solid and solution states. This study used numerous natural and synthetic bismuth mineral samples and whole rock specimens. Full spectrum quantitative X-ray Mapping (XRM) was performed on a JEOL JXA 840 SEM with a Moran Scientific energy dispersive spectroscopy (EDS) Microanalysis system operated at 20kV. A JEOL 8600 EM Probe with a combined EDS and three JEOL wavelength dispersive spectrometers (WDS’s) were also used to perform trace and quantitative analysis. The analysis was undertaken at 15 kV and 20 nA. Drill core samples from the Mineral Hill mine site in regional NSW have been studied to determine the primary bismuth phases at this site which have been associated with a localised Au resource and then related to the known secondary expressions (Figure 1). Experiments have been carried out on a series of synthetic secondary bismuth minerals (Figure 2) to determine the chemical behaviour of these minerals by High Temperature X-ray Diffraction (HTXRD) and Thermogravimetric Analysis coupled with a Differential Scanning Calorimeter (TGA-DSC). These experiments have provided data which can be combined with low temperature solubility studies to give an in-depth understanding into the geochemical roles of secondary bismuth minerals in the supergene environment. For the first time a series of thermodynamic data sets for major and important bismuth mineral phases have been derived. As such a series of useful geochemical models have been

Liberation of Adsorbed and Co-Precipitated Arsenic from Jarosite, Schwertmannite, Ferrihydrite, and Goethite in Seawater

Sea level rise is able to change the geochemical conditions in coastal systems. In these environments, transport of contaminants can be controlled by the stability and adsorption capacity of iron oxides. The behavior of adsorbed and co-precipitated arsenic in jarosite, schwertmannite, ferrihydrite, and goethite in sea water (common secondary minerals in coastal tailings) was investigated. The aim of the investigation was to establish As retention and transport under a marine flood scenario, which may occur due to climate change. Natural and synthetic minerals with co-precipitated and adsorbed As were contacted with seawater for 25 days. During this period As, Fe, Cl, SO4, and pH levels were constantly measured. The larger retention capability of samples with co-precipitated As, in relation with adsorbed As samples, reflects the different kinetics between diffusion, dissolution, and surface exchange processes. Ferrihydrite and schwertmannite showed good results in retaining arsenic, although schwertmannite holding capacity was enhanced due its buffering capacity, which prevented reductive dissolution throughout the experiment. Arsenic desorption from goethite could be understood in terms of ion exchange between oxides and electrolytes, due to the charge difference generated by a low point-of-zero-charge and the change in stability of surface complexes between synthesis conditions and natural media.

In situ study of boron partitioning between calcite and fluid at different crystal growth rates

The boron isotopic and chemical content of carbonates (expressed as δ11B and B/Ca ratios) have been proposed as proxies for seawater carbonate system parameters. Thermodynamic and kinetic effects on δ11B and B partitioning are not yet fully constrained, underscoring the importance of exploring possible effects of growth rate on boron incorporation in synthetic calcium carbonate minerals, which is the focus of this study. Secondary Ion Mass Spectrometry (SIMS) measurements of B/Ca and δ11B were performed on single crystal of calcite synthesized by diffusion of CO2 under controlled conditions from a solution of NH4Cl–CaCl2 doped with boron. Growth rates of calcite (V, nm/s) within crystals grown isothermally at 24.6°C were monitored by sequentially spiking calcite-precipitating fluids with rare earth element (REE) dopants. The REE were analyzed with SIMS at spots that match those locations where B/Ca and δ11B ratios were measured. Values for the boron Nernst partition coefficient, defined as DB=B(calcite)/B(fluid), increase from 0.5 (pHNBS=8.15) to 0.9 (pH=8.00) with values of V increasing from 0.04 to 0.13nm/s. For δ11B behavior, it was not possible to draw conclusive results due to the analytical error (2.2‰; 2σ). pH effects on DB during calcite precipitation, associated with an increase in pH from 8.00 to 8.15, appear to be masked by the competing effects of changing V. We conclude that over the range of growth rates and other conditions investigated in this study, growth rate effects on B partitioning need to be accounted for when using B/Ca ratios in biogenic calcite as a proxy for seawater carbonate system parameters.

ChemInform Abstract: The Largely Unknown Class of Microporous Hybrid Materials: Clays Pillared by Molecules

AbstractReview: 103 refs.

Measurement of non-isothermal oxygen potentials in a Cu–Fe–Ca–S–O liquid during reduction of chalcopyrite in lime and carbon mixtures

The reduction of Indian chalcopyrite concentrates from the Ghatshila mines with carbon was studied in the presence of lime in the temperature range of 1123–1573 K. An attempt was made to determine the oxygen potential corresponding to the selective separation of two metals, copper and iron, during the reduction of chalcopyrite by carrying out electro-motive force (emf) measurements under isochronal heating rate conditions using an yttria-stabilised zirconia solid electrolyte cell with Cu/Cu2O as the reference electrode. The isochronal rate data for oxygen potential measurements were analysed by comparing them with the data from isothermal kinetics studies on the reduction of natural and synthetic chalcopyrite minerals in the above temperature range. The analyses of phases formed were carried out using the X-ray powder diffraction and scanning electron microscopic techniques, which showed the presence of a new quinary solid solution CIII phase. The solid solution phase CIII [Cu2S-CII(FeS⋅CaO)] forms as a result of mixing between the two rhombohedral lattices: high-temperature form of Cu2S and CII (FeO⋅CaS) compounds. The mechanism of reduction of chalcopyrite with carbon in the presence of lime is illustrated by the explanation of the role of the intermediate phases, CII, CIII and matte phases.

The Largely Unknown Class of Microporous Hybrid Materials: Clays Pillared by Molecules

AbstractThe review summarizes recent progress in the field of synthetic clay minerals pillared with organic or metal complex cations (PILCs). We briefly introduce the field of such PILCs and discuss the weaknesses of the state of the art characterization chart of PILCs. When PILCs are made from nanoscopic host materials like natural clay minerals, charge heterogeneity accompanied by interstratification, the turbostratic disorder in the stacking and the influence of the large external surface weaken essential analytical results. Turning to coarse‐grained, well ordered clay minerals synthesized from the melt at temperatures above 1000 K removes all these obstacles and allows to present consistent data underlining the validity of the appealing pillaring concept: Refinement of PILC structures gives information on the pillar‐host interaction and the orientation of pillars in the interlayer space. Two‐dimensional superstructure reflections give direct evidence of the well‐ordered lateral arrangement of pillars. And most importantly, analysis of chemical composition and physisorption isotherms are not corrupted by contributions of large external surfaces and this allows for predicting micropore volume and widths from pillar/host ratios in combination with pillar size/shape. Moreover, recent progress allows fine‐tuning the charge density of the host lattice post‐synthesis. Such deliberate and fine‐graded alteration of the pillar density in turn permits adjusting the pore size in steps as small as 0.1 Å to a given adsorbate and thus will pave the way to maximize adsorption enthalpies and to improve selectivity. This feature is unique to PILCs and is not available to MOFs whose porosity can be adjusted only in steps no smaller than the order of chemical bond lengths. Rational design of microporous hybrid materials with full control over size, shape, and chemical nature of micropores certainly represents the strength and great potential of the pillaring approach.

Modified composites based on mesostructured iron oxyhydroxide and synthetic minerals: A potential material for the treatment of various toxic heavy metals and its toxicity

The composites of mesostructured iron oxyhydroxide and/or commercial synthetic zeolite were investigated for use in the removal of toxic heavy metals, such as cadmium, copper, lead and arsenic, from aqueous solution. Four types of adsorbents, dried alginate beads (DABs), synthetic-zeolite impregnated beads (SZIBs), meso-iron-oxyhydroxide impregnated beads (MIOIBs) and synthetic-zeolite/meso-iron-oxyhydroxide composite beads (SZMIOIBs), were prepared for heavy metal adsorption tests. Laboratory experiments were conducted to investigate the removal efficiencies of cations and anions of heavy metals and the possibility of regenerating the adsorbents. Among these adsorbents, the MIOIBs can simultaneously remove cations and anions of heavy metals; they have high adsorption capacities for lead (60.1mgg−1) and arsenic (71.9mgg−1) compared with other adsorbents, such as DABs (158.1 and 0.0mgg−1), SZIB (42.9 and 0.0mgg−1) and SZMIOIB (54.0 and 5.9mgg−1) for lead and arsenic, respectively. Additionally, the removal efficiency was consistent at approximately 90%, notwithstanding repetitive regeneration. The characteristics of meso-iron-oxyhydroxide powder were confirmed by X-ray diffraction, Brunauer–Emmett–Teller and transmission electron microscopy. We also performed a comparative toxicity study that indicated that much lower concentrations of the powdered form of mesostructured iron oxyhydroxide had stronger cytotoxicity than the granular form. These results suggest that the granular form of meso iron oxyhydroxide is a more useful and safer adsorbent for heavy metal treatment than the powdered form. This research provides promising results for the application of MIOIBs as an adsorbent for various heavy metals from wastewater and sewage.

Mineralogical investigations in metallurgy as a contribution to the affirmation of industrial mineralogy in Serbia

Industrial mineralogy is a part of mineralogy dealing with natural and synthetic minerals, raw materials, secondary raw materials, polymineral materials that originated from the production processes, etc. As applicable, it has been used in the refractories industry, ceramics industry, ferrous and non-ferrous metallurgy, cement industry and other industries. The work aimed at presenting its contribution to the affirmation of industrial mineralogy in Serbia through the results of mineralogical investigations obtained in ferrous metallurgy and copper metallurgy. A larger number of mineralogical investigations, carried out on the materials being characteristic for metallurgical processes and issues of ferrous metallurgy and copper metallurgy, have been stated in this work. Refractory bricks, various types of slag, final flotation waste, copper concentrate, etc. have been investigated. At the same time, the reasons and objectives of performed mineralogical investigations have been given. The results of mineralogical investigations have been shown in detail on two examples. The first are associated with the problems and material in ferrous metallurgy and the second with the material and problems in copper metallurgy. Firstly, the results of mineralogical investigations of casting powders have been shown. They have been investigated for verification of the quality and erosion of the alumographite entry nozzles, that occurred due to their effect. The investigations aimed at increasing the durability (resistance) of the alumographite entry nozzles being utilized in the process of continuous casting of steel. By increasing the durability of entry nozzles the production costs are reduced. The method of X-ray diffraction analysis (XRPD) has been used for investigating the mineralogical composition of casting powders. The results of studying the process of copper concentrate roasting in the fluo-solid reactor have been shown in the second example, with the aim of investigating the transformation degree of the primary ore minerals under various technological parameters. The input material (charge) and roasting products in the reactor (calcine) were investigated by various methods. The investigation results have shown that reactions of mineral transformations are not completed, i.e. they are developing only partially (12-22%), which is the consequence of insufficiently long heating, unsuitable temperature or unfulfilled other parameters, such as for example, a nonuniform grain size. All stated mineralogical investigations and the results shown in this work gave a significant contribution to the affirmation of industrial mineralogy in Serbia.

The mineral signature of the Anthropocene in its deep-time context

Abstract The Earth has shown a systematic increase in mineral species through its history, with three ‘eras’ comprising ten ‘stages’ identified by Robert Hazen and his colleagues ( Hazen et al. 2008 ), the eras being associated with planetary accretion, crust and mantle reworking and the influence of life, successively. We suggest that a further level in this form of evolution has now taken place of at least ‘stage’ level, where humans have engineered a large and extensive suite of novel, albeit not formally recognized minerals, some of which will leave a geologically significant signal in strata forming today. These include the great majority of metals (that are not found natively), tungsten carbide, boron nitride, novel garnets and many others. A further stratigraphic signal is of minerals that are rare in pre-industrial geology, but are now common at the surface, including mullite (in fired bricks and ceramics), ettringite, hillebrandite and portlandite (in cement and concrete) and ‘mineraloids’ (novel in detail) such as anthropogenic glass. These have become much more common at the Earth's surface since the mid-twentieth century. However, the scale and extent of this new phase of mineral evolution, which represents part of the widespread changes associated with the proposed Anthropocene Epoch, remains uncharted. The International Mineralogical Association (IMA) list of officially accepted minerals explicitly excludes synthetic minerals, and no general inventory of these exists. We propose that the growing geological and societal significance of this phenomenon is now great enough for human-made minerals to be formally listed and catalogued by the IMA, perhaps in conjunction with materials science societies. Such an inventory would enable this phenomenon to be placed more effectively within the context of the 4.6 billion year history of the Earth, and would help characterize the strata of the Anthropocene.

Crystallinity and compositional changes in carbonated apatites: Evidence from 31P solid-state NMR, Raman, and AFM analysis.

Solid-state (magic-angle spinning) NMR spectroscopy is a useful tool for obtaining structural information on bone organic and mineral components and synthetic model minerals at the atomic-level. Raman and 31P NMR spectral parameters were investigated in a series of synthetic B-type carbonated apatites (CAps). Inverse 31P NMR linewidth and inverse Raman PO43- ν1 bandwidth were both correlated with powder XRD c-axis crystallinity over the 0.3-10.3 wt% CO32- range investigated. Comparison with bone powder crystallinities showed agreement with values predicted by NMR and Raman calibration curves. Carbonate content was divided into two domains by the 31P NMR chemical shift frequency and the Raman phosphate ν1 band position. These parameters remain stable except for an abrupt transition at 6.5 wt% carbonate, a composition which corresponds to an average of one carbonate per unit cell. This near-binary distribution of spectroscopic properties was also found in AFM-measured particle sizes and Ca/P molar ratios by elemental analysis. We propose that this transition differentiates between two charge-balancing ion-loss mechanisms as measured by Ca/P ratios. These results define a criterion for spectroscopic characterization of B-type carbonate substitution in apatitic minerals.

Raman spectroscopic properties and Raman identification of CaS‐MgS‐MnS‐FeS‐Cr2FeS4 sulfides in meteorites and reduced sulfur‐rich systems

AbstractRaman spectra were acquired on a series of natural and synthetic sulfide minerals, commonly found in enstatite meteorites: oldhamite (CaS), niningerite or keilite ((Mg,Fe)S), alabandite (MnS), troilite (FeS), and daubreelite (Cr2FeS4). Natural samples come from three enstatite chondrites, three aubrites, and one anomalous ungrouped enstatite meteorite. Synthetic samples range from pure endmembers (CaS, FeS, MgS) to complex solid solutions (Fe, Mg, Ca)S. The main Raman peaks are localized at 225, 285, 360, and 470 cm−1 for the Mg‐rich sulfides; at 185, 205, and 285 cm−1 for the Ca‐rich sulfides; at 250, 370, and 580 cm−1 for the Mn‐rich sulfides; at 255, 290, and 365 cm−1 for the Cr‐rich sulfides; and at 290 and 335 cm−1 for troilite with, occasionally, an extra peak at 240 cm−1. A peak at 160 cm−1 is present in all Raman spectra and cannot be used to discriminate between the different sulfide compositions. According to group theory, none of the cubic monosulfides oldhamite, niningerite, or alabandite should present first‐order Raman spectra because of their ideal rocksalt structure. The occurrence of broad Raman peaks is tentatively explained by local breaking of symmetry rules. Measurements compare well with the infrared frequencies calculated from first‐principles calculations. Raman spectra arise from activation of certain vibrational modes due to clustering in the solid solutions or to coupling with electronic transitions in semiconductor sulfides.

Theoretical considerations of machining with grinding wheels

Grinding is one of the most versatile methods of removing material from machine parts by the cutting action of the countless hard and sharp abrasive particles of a revolving grinding wheel. It works by forcing the abrasive grains into the surface of the workpiece so that each grain cuts away a small bit of material in the form of chips. Abrasive grinding wheel is an expendable wheel that carries an abrasive compound on its periphery. They are made of small, sharp and very hard natural or synthetic abrasive minerals, bonded together in a matrix to form a wheel. The paper presents a review of some of the characteristics as well as theoretical considerations of operations of abrasive grinding wheel. The relationships among the various grinding parameters; the radial force f, the force on individual grit of grinding wheel F, velocity of grinding wheelg Vg, velocity of work piecew Vw, the wheel diameterg Dg, and the diameter of the work piece Dw were established for given grinding operations.

Luminescence spectroscopy and imaging: analytical advances and perspectives in the Earth sciences and related disciplines

This special issue is devoted to review articles on various themes and topics related to the application of luminescence spectroscopy and luminescence-based imaging in the Earth sciences and related disciplines. It was compiled on the occasion of the CORALS–2013, the third Conference on Raman and Luminescence Spectroscopy in the Earth sciences (July 3–6, 2013, Vienna, Austria). In contrast to the two previous CORALS conferences, held in Mainz, Germany (2009), and Madrid, Spain (2011), the CORALS–2013 was not focused preferentially on research in Lunar and planetary sciences, but it was open explicitly to applications of Raman and luminescence spectroscopy in all fields of the Earth sciences and related disciplines. In view of its broad profile as regards scientific content, the conference therefore seemed to be an excellent occasion to summarise the current state of the research. This, however, has already been done just recently for the Raman technique: A wide range of applications of Raman spectroscopic analyses has been presented comprehensively in volume 12 of the EMU Notes in Mineralogy (J. Dubessy, M.-C. Caumon, F. Rull, Eds.: Applications of Raman spectroscopy to Earth sciences and cultural heritage. European Mineralogical Union, 2012), and the use of Raman-based images in the Earth sciences has been summarised in an extended review chapter contained in volume 168 of Springer Series in Optical Sciences (A. Zoubir, Ed.: Raman imaging—Techniques and applications. Springer, Berlin Heidelberg, 2012). This special issue therefore focuses on luminescence techniques only. Other than most special issues related to conferences, this present issue dos not consist of a selection of research contributions that were presented during the conference. Rather, a number of review articles were invited well in advance, with the aim to compile a summary of the current status of luminescence seen from the Earth-sciences perspective, by the time the conference starts. Not all of our invitations were accepted, and not all of the submissions received could be published. For these reasons, several important fields (such as ion-beam luminescence, dosimetry based on afterglow-type luminescence, or the use of internal textures of minerals observed in luminescence images to assist isotope geochronology techniques) are not covered here; the summary hence must remain incomplete. We are nevertheless convinced that the eight review papers in this volume present a well-balanced selection of articles documenting the broad range of recent research activities and advances. To underline and illustrate the versatility of luminescence techniques in studying geological samples and synthetic minerals, we present a number of spectra and images in Fig. 1. We feel, however, obliged to add that at present, applications of luminescence spectroscopy and imaging applied in the Earth sciences are way more versatile than it can be visualised in a single paper or even a single figure. This assessment is supported by the range of topics presented in the present issue. Barbin contributed a summary of the application of the cathodoluminescence (CL) technique to the study of biogenic materials. As an example, the CL emission of trace-Mn in carbonate minerals is discussed, whose incorporation mechanism depends on the primary growth Editorial handling: R. Abart