European Journal of Mineralogy最新文献

{"title":"Non-destructive determination of the biotite crystal chemistry using Raman spectroscopy: how far we can go?","authors":"S. Aspiotis, J. Schlüter, G. Redhammer, B. Mihailova","doi":"10.5194/ejm-34-573-2022","DOIUrl":"https://doi.org/10.5194/ejm-34-573-2022","url":null,"abstract":"Abstract. Raman spectroscopy combined with electron microprobe analysis as well as\u0000Mössbauer spectroscopy was applied to a series of 18 samples along the\u0000phlogopite (KMg3AlSi3O10(OH)2)–annite\u0000(KFe32+AlSi3O10(OH)2) join to establish a truly\u0000non-destructive method for crystallochemical characterization of biotite\u0000(A1M3T4O10X2, M3 = M1M2M2). The Raman\u0000scattering arising from the framework (15–1215 cm−1) and OH-stretching\u0000phonon modes (3000–3900 cm−1) was used to build up correlation trends\u0000between the Raman spectral features and crystal chemistry of biotite. We\u0000show that (a) the contents of MMg, MFe2+, and\u0000MFe3+ contents can be quantified with a relative error of\u0000∼ 6 %, ∼ 6 %, and ∼ 8 %,\u0000respectively, by combining the integrated intensities of the OH-stretching\u0000peaks assigned to various M1M2M2 local configurations with the wavenumber of\u0000the MO6 vibrational mode near 190 cm−1; (b) the MTi content\u0000can be estimated from the peak position and FWHM (full width at half maximum) of the second strongest\u0000TO4-ring mode at ∼ 680 cm−1, with a precision of\u000022 %; (c) the content of TSi can be estimated from the position of\u0000the second peak related to TO4-ring vibrations near 650 cm−1; (d) for phlogopite the TAl content can indirectly be calculated by knowing\u0000the amount of TSi, whereas for annite it is hindered by the plausible\u0000presence of TFe3+; (e) the AK content can be quantified by\u0000the position of the peak generated by T-Ob-T bond-stretching-and-bending vibration at ∼ 730 cm−1; and (f) interlayer-deficient biotites and F-rich phlogopite can be identified via\u0000their unique OH-stretching Raman peaks around 3570 cm−1 and 3695 cm−1, respectively. Our results show a potential tool for\u0000non-destructive quantitative estimations of the major (Mg, Fe, Si, Al, K)\u0000and minor (Ti) elements of the crystal chemistry of the biotite mineral\u0000group by using a non-destructive technique such as Raman spectroscopy,\u0000although its sensitivity is generally lower than that of electron microprobe\u0000analysis and therefore cannot detect trace elements. This is fundamental\u0000within the framework of cultural heritage where samples cannot be powdered\u0000or disassembled.\u0000","PeriodicalId":11971,"journal":{"name":"European Journal of Mineralogy","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45109600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tin weathering experiment set by nature for 300 years: natural crystals of the anthropogenic mineral hydroromarchite from Creussen, Bavaria, Germany","authors":"N. Dubrovinskaia, Maria Messingschlager, L. Dubrovinsky","doi":"10.5194/ejm-34-563-2022","DOIUrl":"https://doi.org/10.5194/ejm-34-563-2022","url":null,"abstract":"Abstract. Hydroromarchite is a mineral that so far has been found only in a\u0000few locations in the world and recognized as a common product of submarine\u0000corrosion of pewter artefacts. Here we report a new locality for this rare\u0000mineral found at the Saint James Church archaeological site in Creussen,\u0000Germany. There it appeared to be a product of weathering of a tin artefact\u0000(a tin button) buried in soil of the churchyard for about 300 years. The\u0000mineral, found in paragenesis with romarchite and cassiterite, was\u0000identified using single-crystal X-ray diffraction.\u0000","PeriodicalId":11971,"journal":{"name":"European Journal of Mineralogy","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-11-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43518848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relatively oxidized conditions for diamond formation at Udachnaya (Siberia)","authors":"L. Faccincani, V. Cerantola, F. Nestola, P. Nimis, L. Ziberna, L. Pasqualetto, A. Chumakov, J. Harris, M. Coltorti","doi":"10.5194/ejm-34-549-2022","DOIUrl":"https://doi.org/10.5194/ejm-34-549-2022","url":null,"abstract":"Abstract. Thanks to the physical strength of diamonds and their relatively unreactive\u0000chemical nature, their mineral inclusions may remain exceptionally preserved\u0000from alteration processes and chemical exchanges with surrounding minerals,\u0000fluids and/or melts following diamond formation. Cr-bearing spinels are\u0000relatively common inclusions found in peridotitic diamonds and important\u0000oxybarometers providing information about the oxygen fugacity (fO2)\u0000of their source mantle rocks. Here, we investigated a\u0000magnesiochromite–olivine touching pair in a diamond from the Udachnaya\u0000kimberlite (Siberia) by in situ single-crystal X-ray diffraction and\u0000energy-domain synchrotron Mössbauer spectroscopy, aiming to constrain\u0000the physical–chemical conditions of diamond formation and to explore the\u0000redox state of this portion of the Siberian craton when the diamond was\u0000formed. The P–T–fO2 entrapment conditions of the inclusion pair, determined\u0000by thermo- and oxybarometric analyses, are ∼ 5.7(0.4) GPa and ∼ 1015(50) ∘C (although entrapment at higher T\u0000and re-equilibration during subsequent mantle storage are also possible) and\u0000fO2 near the enstatite–magnesite–olivine–diamond (EMOD) buffer. The\u0000determined fO2 is similar to, or slightly more oxidized than, those\u0000of xenoliths from Udachnaya, but whilst the xenoliths last equilibrated with\u0000the surrounding mantle just prior to their entrainment in the kimberlite at\u0000∼ 360 Ma, the last equilibration of the inclusion pair is much\u0000older, occurring at 3.5–3.1, ∼ 2 or ∼ 1.8 Ga before final encapsulation in its host diamond. Hence, the similarity\u0000between xenoliths and inclusion fO2 values indicates that the modern redox\u0000state of this portion of the Siberian lithosphere was likely attained\u0000relatively early after its formation and may have persisted for billions of\u0000years after diamond formation, at least at the local scale. Moreover, the\u0000oxygen fugacity determination for the inclusion pair provides direct\u0000evidence of diamond formation near the EMOD buffer and is consistent with\u0000recent models suggesting relatively oxidized, water-rich CHO fluids as the\u0000most likely parents for lithospheric diamonds.\u0000","PeriodicalId":11971,"journal":{"name":"European Journal of Mineralogy","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42867306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Corresponding relationship between characteristic birefringence, strain, and impurities in Zimbabwean mixed-habit diamonds revealed by mapping techniques","authors":"Chengyang Sun, Taijin Lu, Mingyue He, Zhonghua Song, Yi Deng","doi":"10.5194/ejm-34-539-2022","DOIUrl":"https://doi.org/10.5194/ejm-34-539-2022","url":null,"abstract":"Abstract. Birefringence in diamond is an optical phenomenon related\u0000to strain and various defects in crystal lattices. Despite extensive\u0000investigations being done to characterize and quantify it, there is still\u0000controversy about its origin in diamond lattices. Here we report the\u0000relationship between the distribution of birefringence patterns observed\u0000under cross-polarized light, strain features analyzed by Raman mapping, and\u0000the impurity characteristics revealed by Fourier transform infrared spectroscopy (FTIR) mapping in natural mixed-habit\u0000diamonds. It was deduced that the plastic deformation was enhanced with\u0000higher tensile residual stress, and nitrogen and VN3H defects\u0000were more enriched as a result of the temperature increase during\u0000crystallization, at growth bands showing straight birefringence patterns and\u0000the relative enrichment of graphite inclusions. These results provided solid\u0000data and insights for birefringence-related properties in diamond and\u0000correlated the occurrence of birefringence with diamond spectroscopic\u0000properties, which promoted the understanding of the formation of\u0000birefringence in natural diamonds and would be helpful for the synthesis of\u0000high-quality, birefringence-free diamonds.\u0000","PeriodicalId":11971,"journal":{"name":"European Journal of Mineralogy","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44781034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"TotBlocks: exploring the relationships between modular rock-forming minerals with 3D-printed interlocking brick modules","authors":"Derek. D. V. Leung, Paige E. dePolo","doi":"10.5194/ejm-34-523-2022","DOIUrl":"https://doi.org/10.5194/ejm-34-523-2022","url":null,"abstract":"Abstract. Many rock-forming chain and sheet silicate minerals,\u0000i.e., pyroxenes, amphiboles, micas, and clay minerals, are built from shared\u0000chemical building blocks known as T-O-T modules. Each module consists of two\u0000opposing chains of vertex-sharing silica tetrahedra (T), which vertically\u0000sandwich a ribbon of edge-sharing metal–oxygen octahedra (O) in a T-O-T\u0000configuration. These minerals are both abundant and diverse in the\u0000lithosphere because T-O-T modules are chemically versatile (incorporating\u0000common crustal elements, e.g., O, Si, Al, Fe, and Mg) and structurally\u0000versatile (varying as a function of module width and linkage type) over a\u0000wide range of chemical and physical conditions. Therefore, these minerals\u0000lie at the center of understanding geological processes. However, their\u0000diversity leads to the minerals developing complex, 3D\u0000crystal structures, which are challenging to communicate. Ball-and-stick\u0000models and computer visualization software are the current methods for\u0000communicating the crystal structures of minerals, but both methods have\u0000limitations in communicating the relationships between these complex crystal\u0000structures. Here, we investigate the applications of 3D printing in\u0000communicating modular mineralogy and crystal structures. The open-source\u0000TotBlocks project consists of 3D-printed, T-O-T interlocking bricks, based on\u0000ideal polyhedral representations of T and O modules, which are linked by\u0000hexagonal pegs and slots. Using TotBlocks, we explore the relationships\u0000between modular minerals within the biopyribole (biotite–pyroxene–amphibole)\u0000and palysepiole (palygorskite–sepiolite) series. The bricks can also be\u0000deconstructed into T and O layer modules to build other mineral structures\u0000such as the brucite, kaolinite–serpentine, and chlorite groups. Then, we use\u0000the T-O-T modules within these minerals to visually investigate trends in their\u0000properties, e.g., habit, cleavage angles, and symmetry/polytypism. In\u0000conclusion, the TotBlocks project provides an accessible, interactive, and\u0000versatile way to communicate the crystal structures of common rock-forming\u0000minerals.\u0000","PeriodicalId":11971,"journal":{"name":"European Journal of Mineralogy","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42015358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Studies on the local structure of the F ∕ OH site in topaz by magic angle spinning nuclear magnetic resonance and Raman spectroscopy","authors":"A. Loges, G. Scholz, N. de Sousa Amadeu, Jingjing Shao, D. Schultze, Jeremy Fuller, B. Paulus, F. Emmerling, T. Braun, T. John","doi":"10.5194/ejm-34-507-2022","DOIUrl":"https://doi.org/10.5194/ejm-34-507-2022","url":null,"abstract":"Abstract. The mutual influence of F and OH groups in neighboring\u0000sites in topaz (Al2SiO4(F,OH)2) was investigated using magic\u0000angle spinning nuclear magnetic resonance (MAS NMR) and Raman spectroscopy.\u0000The splitting of 19F and 1H NMR signals, as well as the OH Raman band,\u0000provides evidence for hydrogen bond formation within the crystal structure.\u0000Depending on whether a given OH group has another OH group or fluoride as\u0000its neighbor, two different hydrogen bond constellations may form: either\u0000OH⋯O⋯HO or F⋯H⋯O. The proton accepting oxygen was determined to be part of the\u0000SiO4 tetrahedron using 29Si MAS NMR. Comparison of the MAS NMR\u0000data between an OH-bearing and an OH-free topaz sample confirms that the\u000019F signal at −130 ppm stems from F− ions that take part in\u0000H⋯F bonds with a distance of\u0000∼ 2.4 Å, whereas the main signal at −135 ppm belongs to\u0000fluoride ions with no immediate OH group neighbors. The Raman OH sub-band at\u00003644 cm−1 stems from OH groups neighboring other OH groups, whereas the\u0000sub-band at 3650 cm−1 stems from OH groups with fluoride neighbors,\u0000which are affected by H⋯F bridging. The\u0000integrated intensities of these two sub-bands do not conform to the expected\u0000ratios based on probabilistic calculations from the total OH concentration.\u0000This can be explained by (1) a difference in the polarizability of the OH bond\u0000between the different hydrogen bond constellations or (2) partial order\u0000or unmixing of F and OH, or a combination of both. This has implications for\u0000the quantitative interpretation of Raman data on OH bonds in general and\u0000their potential use as a probe for structural (dis-)order. No indication of\u0000tetrahedrally coordinated Al was found with 27Al MAS NMR, suggesting\u0000that the investigated samples likely have nearly ideal Al/Si ratios, making\u0000them potentially useful as high-density electron microprobe reference\u0000materials for Al and Si, as well as for F.\u0000","PeriodicalId":11971,"journal":{"name":"European Journal of Mineralogy","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43521681","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Weathering of stannite–kësterite [Cu2(Fe,Zn)SnS4] and the environmental mobility of the released elements","authors":"P. Haase, S. Kiefer, K. Pollok, P. Drahota, J. Majzlan","doi":"10.5194/ejm-34-493-2022","DOIUrl":"https://doi.org/10.5194/ejm-34-493-2022","url":null,"abstract":"Abstract. The sulfidic waste dumps of the historical mining sites Giftkies\u0000and Kaňk (Czech Republic) have been exposed to a temperate climate over\u0000decades. This exposure generated low-pH conditions caused by metal sulfide\u0000decomposition. Tin sulfides of the stannite–kësterite series\u0000[Cu2(Fe,Zn)SnS4] are common Sn minerals in the ores at the\u0000investigated sites. They decompose under acidic and oxidizing conditions and\u0000form in situ secondary precipitates. Compositional analyses of primary and\u0000secondary minerals were collected by electron microprobe to track the\u0000environmental mobility of the released elements during weathering.\u0000Transmission electron microscopy revealed a diffusion-driven alteration of\u0000stannite to Sn-rich chalcopyrite and the precipitation of native copper and\u0000silver from stannite. In assemblages containing arsenopyrite, an in situ and\u0000amorphous Sn–Fe–As (SFA)-rich phase precipitated close to the Sn sulfide.\u0000The SFA precipitate contains very little sulfur, which was probably released\u0000to the aqueous phase as oxidized species, whereas small amounts of Cu and Zn\u0000were captured by the SFA. This precipitate is metastable and acts as a\u0000temporaneous sink for mobile elements (Cu, Zn) and elements derived from\u0000acid-soluble silicates and phosphates (Ca, Si, Al, and P). With advanced\u0000weathering, complex redox reactions result in the precipitation of magnetite\u0000as an oxidation product of the sulfidic material under oxidative conditions.\u0000The stable minerals goethite and cassiterite mark the end of the weathering\u0000sequence and crystallized from the amorphous SFA precipitate.\u0000","PeriodicalId":11971,"journal":{"name":"European Journal of Mineralogy","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45786610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A snapshot of the transition from monogenetic volcanoes to composite volcanoes: case study on the Wulanhada Volcanic Field (northern China)","authors":"D. Luo, M. Reichow, T. Hou, M. Santosh, Zhaochong Zhang, Meng Wang, Jingyi Qin, Daoming Yang, Ronghao Pan, Xudong Wang, F. Holtz, R. Botcharnikov","doi":"10.5194/ejm-34-469-2022","DOIUrl":"https://doi.org/10.5194/ejm-34-469-2022","url":null,"abstract":"Abstract. The transition processes from monogenetic volcanoes to composite volcanoes\u0000are poorly understood. The Late Pleistocene to Holocene intraplate\u0000monogenetic Wulanhada Volcanic Field (WVF) in northern China provides a\u0000snapshot of such a transition. Here we present petrographic observations,\u0000mineral chemistry, bulk rock major and trace element data, thermobarometry,\u0000and a partial melting model for the WVF to evaluate the lithology and partial\u0000melting degree of the mantle source, the crystallization conditions, and\u0000pre-eruptive magmatic processes occurring within the magma plumbing system.\u0000The far-field effect of India–Eurasia collision resulted in a relatively high\u0000degree (10 %–20 %) of partial melting of a carbonate-bearing eclogite\u0000(∼ 3 wt % carbonate; Gt/Cpx ≈ 2 : 8, where Gt denotes garnet and Cpx denotes clinopyroxene) followed\u0000by interaction with ambient peridotite. The primary melts ascended to the\u0000depth of the Moho (∼ 33–36 km depth), crystallized olivine,\u0000clinopyroxene and plagioclase at the temperature of 1100–1160 ∘C\u0000with the melt water contents of 1.1 wt %–2.3 wt %. Part of the primary melt\u0000interacted with the lithospheric mantle during ascent, resulting in an\u0000increase in the MgO contents and a decrease in the alkaline contents. The\u0000modified magma was subsequently directly emplaced into the middle crust\u0000(∼ 23–26 km depth) and crystallized olivine, clinopyroxene and\u0000plagioclase at the temperature of 1100–1160 ∘C. The primary melts\u0000from the same mantle sources migrated upward to the two-level magma\u0000reservoirs to form minerals with complex textures (including reverse and\u0000oscillatory zoning and sieve texture). Magma erupted along the NE–SW-striking basement fault and the NW–SE-striking Wulanhada–Gaowusu fault in\u0000response to the combined effects of regional tectonic stress and magma\u0000replenishment. The crustal magma reservoir in the WVF may represent a snapshot\u0000of the transition from monogenetic volcanoes to composite volcanoes. It is\u0000possible to form a composite volcano with large magma volumes and complex\u0000compositions if the magma is continuously supplied from the source and\u0000experiences assimilation and fractional crystallization processes in the\u0000magma plumbing system at crustal depth.\u0000","PeriodicalId":11971,"journal":{"name":"European Journal of Mineralogy","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47380481","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ferri-taramite, a new member of the amphibole supergroup, from the Jakobsberg Mn–Fe deposit, Värmland, Sweden","authors":"D. Holtstam, F. Cámara, A. Karlsson, H. Skogby, T. Zack","doi":"10.5194/ejm-34-451-2022","DOIUrl":"https://doi.org/10.5194/ejm-34-451-2022","url":null,"abstract":"Abstract. Ferri-taramite (IMA CNMNC 2021-046), ideally\u0000ANaB(CaNa)C(Mg3Fe23+)(Si6Al2)O22W(OH)2,\u0000occurs in skarn from the Jakobsberg manganese mine, Värmland, Sweden.\u0000Associated minerals are celsian, phlogopite, aegirine-augite, andradite, hancockite,\u0000melanotekite, microcline (var. hyalophane), calcite, baryte, prehnite,\u0000macedonite and oxyplumboroméite. Conditions of formation, close to peak\u0000metamorphism (at circa 650 ∘C and 0.4 GPa), include silica\u0000undersaturation, a slightly peralkaline character and relatively high\u0000oxygen fugacities. Ferri-taramite forms poikiloblastic crystals up to 5 mm\u0000and is dark brownish black with a yellowish grey streak. The amphibole is\u0000brittle with an uneven to splintery fracture. Cleavage parallel to\u0000{110} is good. Hardness (Mohs) is ∼ 6,\u0000and Dcalc=3.227(5) g cm−3. Holotype ferri-taramite\u0000has the experimental unit formula\u0000A(Na0.79K0.16Pb0.01)Σ0.96B(Ca1.26Na0.72Mn0.022+)Σ2C(Mg2.66Mn0.582+Fe0.162+Zn0.02Fe1.263+\u0000Al0.26Ti0.06)Σ5.00T(Al1.86Si6.14)Σ8O22W(OH)2, based on chemical analyses (EDS, laser-ablation ICP-MS) and\u0000spectroscopic (Mössbauer, infrared) and single-crystal X-ray\u0000diffraction data. The mineral is optically biaxial (–), with α=1.670(5), β=1.680(5) and γ=1.685(5) in white light and\u00002Vmeas=70(10)∘ and 2Vcalc=70.2∘.\u0000Ferri-taramite is distinctly pleochroic in transmitted light, with X pale\u0000yellow, Y dark brown, Z yellowish brown and absorption Y>Z>X. The eight strongest reflections in the X-ray powder pattern\u0000(d values (in Å), Irel, hkl) are 8.44, 60, 110; 3.392, 25, 131;\u00003.281, 39, 240; 3.140, 100, 310; 2.816, 45, 330; 2.7104, 38, 151;\u00001.3654, 26, 461; and 1.4451, 33, 6‾61. Refined unit-cell parameters from\u0000single-crystal diffraction data are a=9.89596(13), b=18.015(2), c=5.32164(7) Å, β=105.003(13)∘ and V=916.38(2) Å3 for Z=2. Refinement of the crystal structure yielded R=2.26 % for 2722 reflections with Io>2σ(I). The\u0000Mn2+ and Fe2+ ions show preference for the M1 and M3 octahedrally\u0000coordinated sites, whereas Fe3+ is strongly ordered at M2. The A-group\u0000cations, K and Na, are split over two subsites, A(m) and A(2), respectively.\u0000","PeriodicalId":11971,"journal":{"name":"European Journal of Mineralogy","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-10-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47328676","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New secondary phosphate mineral occurrences and their crystal chemistry, at the Hagendorf Süd pegmatite, Bavaria","authors":"E. Keck, I. Grey, C. MacRae, Stephanie Boer, R. Hochleitner, Christian Rewitzer, W. G. Mumme, A. Glenn, C. Davidson","doi":"10.5194/ejm-34-439-2022","DOIUrl":"https://doi.org/10.5194/ejm-34-439-2022","url":null,"abstract":"Abstract. First occurrences from the Hagendorf Süd pegmatite of the secondary\u0000phosphate minerals kenngottite,\u0000Mn32+Fe43+(PO4)4(OH)6(H2O)2;\u0000allanpringite, Fe33+(PO4)2(OH)3 ⚫ 5H2O; iangreyite,\u0000Ca2Al7(PO4)2(PO3OH)2(OH,F)15 ⚫ 8H2O; and nizamoffite, MnZn2(PO4)2(H2O)4, are\u0000reported with characterisation of their crystal chemistry and phase\u0000associations. A synchrotron single-crystal structure refinement for\u0000kenngottite shows that it has the same level of disordering (75 %/25 %)\u0000of Fe3+ in adjacent octahedra along the 5 Å axis as for\u0000type-locality kenngottite from Krásno, Czech Republic. This is explained\u0000in terms of 1 : 1 fine-scale mixing of domains of ordered kenngottite-type and\u0000souzalite-type structures. Allanpringite occurs in an unusual epitaxial\u0000relationship to associated strunzite. The epitaxy is explained by the close\u0000metrical and structural match of common planes in the two minerals, (010)\u0000for allanpringite and (100) for strunzite. Iangreyite occurs in close\u0000association with perhamite in 30 µm spheroids. The characterisation\u0000results support a paragenesis of iangreyite from perhamite by selective\u0000leaching of silica from the layer structure of perhamite and rejoining of\u0000the layers by fusion of AlO4 tetrahedra from adjacent layers into\u0000AlO2(OH)3 trigonal bipyramids.\u0000","PeriodicalId":11971,"journal":{"name":"European Journal of Mineralogy","volume":" ","pages":""},"PeriodicalIF":2.1,"publicationDate":"2022-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42146632","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}