Anningite-(Ce) ideally (Ca0.5Ce4+0.5)(VO4), was found within a phosphate coprolite from the sand-dominated sediments of the Gara Samani Formation, Algeria. As a tetragonal anhydrous vanadate, this mineral is classified in the xenotime group. It occurs in rock cavities and forms small (typically up to 100 μm in length) sheaf-like aggregates composed of crystals 30–40 μm in length and ∼7 μm in diameter. Anningite-(Ce) crystals are green with a vitreous lustre. No cleavage is observed and the fracture is uneven or conchoidal. Its empirical formula, calculated on the basis of 4 oxygen atoms, can be written as (Ca0.52Ce4+0.47Y3+0.01)Σ1.00[(VO4)0.88(PO4)0.05(SO4)0.06(SiO4)0.01]Σ1.00. The calculated density is 3.887 g/cm3. Anningite-(Ce) is tetragonal with space group I41/amd and unit-cell parameters a = 7.1500(4) Å, c = 6.3343(7) Å, and V = 323.82(5) Å3. Anningite-(Ce) is isostructural with wakefieldite-(Ce).

The petrographic and geochemical characterisation of the diagenetic calcite and dolomite associated with carbonate-hosted ore deposits can contribute to a better understanding of mineralisation mechanisms. The lower Carnian Breno Formation and Calcare Metallifero Bergamasco in the Dossena area (Gorno mining district, Lombardy Basin, Southern Alps) are two shallow marine carbonate lithostratigraphic units hosting Alpine-type Pb-Zn-F-Ba ores. Several interpretations have been proposed for the genesis of mineralisation in these Triassic carbonates: syngenetic from submarine exhalations linked to the Ladinian–Carnian volcanism; or Alpine-type syngenetic to epigenetic in burial settings by hydrothermal fluids, during Early–Middle Jurassic rifting. Recent studies propose that ores formed in shallow burial settings (tens to few hundreds of metres), precipitated from hydrothermal fluids related to Triassic magmatism, prior to the Early Jurassic rifting.

Petrographic analysis, δ18O data, REEYN normalised patterns, calculated element ratios and lanthanum, cerium and europium normalised anomalies suggest precipitation of the saddle dolomite and calcite cements, filling-fractures preceding and post-dating the mineralisation, from low temperature (<200°C) hydrothermal fluids. The geochemistry of these fluids was influenced by seawater and burial basinal brines. REEYN patterns and Y/Ho ratios suggest the interaction of these fluids with Permian and Ladinian–Carnian siliciclastic and volcaniclastic deposits and/or with the Variscan metamorphic basement, which are possible sources for metals.

The identified paragenesis supports a hydrothermal epigenetic origin for the mineralisation, at burial depths not shallower than 300 m. In fact, pre-mineralisation fractures filled by saddle dolomite and calcite cements cross-cut voids occluded by burial sparite cements and stylolites in an already lithified host rock, affected by burial compaction and pressure solution.

These conclusions may contribute to the understanding of other global occurrences of carbonate-hosted Pb-Zn mineralisation, providing new insights into complex dolomite and calcite paragenesis preceding and following the ore formation.

Crystal-chemical features of high-calcium and hypercalcium eudialyte-group minerals (EGMs) from a carbonatite-related rock of the Tamazeght peralkaline complex, High Atlas Mountains, Morocco were studied using electron probe microanalysis, single-crystal X-ray structure analysis, infrared and Raman spectroscopy. The major components of the host rock are calcite, fluorite and EGMs; aegirine–augite is present in subordinate amounts. The specific features of the studied EGMs are chemical heterogeneity, a complex zoning, reaction zones around calcite and apatite inclusions, Na- and Cl-deficiency, high contents of Ca, Mn, REE, Nb, carbonate and H-bearing groups, positive correlation between Nb and Mn and negative correlations between the pairs Fe–Mn and Zr–Mn. These features confirm previous assumptions about the role of infiltration of carbonatite fluid rich in Ca, Mn, REE, Nb, CO2 and H2O and a depletion of Cl in the remaining fluid after the crystallization of sodalite at the expense of nepheline in the formation of carbonatite-related rocks of the Tamazeght complex. The crystal structure of a single-crystal fragment extracted from the Nb-rich zone refined to R1 = 0.0335 has shown a high degree of ordering of Na, REE and H3O+ and the dominance of Fe3+ at the M2 site with five-fold coordination. The composition of EGMs from the reaction zones around calcite and apatite inclusions corresponds to Mn-dominant (with Mn > Fe at the M2 site) analogue of feklichevite with the simplified formula Ca3(Na,K)9(H3O)3Ca6Zr3(Mn2+,Fe3+,Zr)3NbSi(Si24O72)(OH,H2O)5(F,Cl)2/3(CO3)1/3.

Eleven chert samples from various geographical and geological locations and ages were heat treated, with two of the samples also undergoing in situ X-ray diffraction (XRD) during heat treatment. Characterisation was performed using X-ray fluorescence (XRF), XRD and Raman spectroscopy. The results indicated that the presence of moganite in cherts is independent of whether they are quartzitic or cristobalitic/tridymitic. After heating, cherts cannot be differentiated into these two types using XRD, as all the samples might contain quartz, cristobalite and tridymite. Heat treatment induced transformations in both siliceous and non-siliceous phases, forming new crystalline phases. The observed transformations at 1000°C agree with the literature data. The combination of XRD and Raman spectroscopy is crucial for comprehensive chert analysis, with Raman methods detecting lower concentrations and textural variations than XRD. A correlation exists between chert type (quartzitic or cristobalitic/tridymitic), i.e. mineralogy and age, but not between elemental composition and age. In situ XRD during heating shows distinct crystalline transformations. These transformations can affect significantly the properties of the cherts and has implications for conservation and provenance studies of archaeological tools. The analytical tools used to characterise the mineralogy of cherts are a fast and efficient alternative to conventional petrographic microscopy, especially in the case of heat-treated cherts.

In this work, we evaluated the biological and geological contributions to the formation and preservation of the oxidation zones in Ľubietová-Podlipa, Ľubietová-Svätodušná, Poniky-Farbište and Špania Dolina-Piesky. This case study highlights the importance of the biological contribution to weathering processes of ore deposits. It may be extended to other similar sites in order to assess the magnitude of biological input. Using U-Pb dating, secondary minerals from Podlipa were dated to 22 ± 6 and 19 ± 4 Ma (Lower Miocene). At this time, this region experienced deep weathering under a humid and warm climate and tectonic quiescence. The isotopic (O, H) composition of the secondary minerals shows that they formed from Lower Miocene meteoric water under surface temperatures. The δ13CPDB values in malachite (–19 to –17‰) document a biological source of C, from soil CO2. The δ18OVSMOW values of the PO4 groups in the accessory fluorapatite in the host rocks (1.8 ± 1.7‰, 1σ) and pseudomalachite in the oxidation zone (12.1 ± 2.9‰, 1σ) show substantial biological P input into the oxidation zone. A biogenic source of both C and P agrees well with the palaeoclimatic constraints based on the radiometric dating. The oxidation zones at Podlipa, Svätodušná and Farbište are contemporaneous with kaolin crusts in the same area; they were all preserved only where they were covered by young (14–12 Ma) volcanic rocks and exposed recently by erosion. The other oxidation zones in the Tatric and Veporic units, if they existed, were destroyed by the Pliocene uplift of these units. The oxidation zone at Piesky is younger, dated to 2.5 Ma (Early Pleistocene) when the global temperatures in interglacials were similar to the present, decreasing in glacials by ∼4°C. The different climate at this time is manifested by scattered δ13C values, reflecting surface temperature and vegetation fluctuations at this time.

The new mineral pendevilleite-(Y) (IMA 2022-054), ideally Mg2Y3Al(UO2)2(CO3)7(OH)6(H2O)16, was found in the famous Kamoto-East open-cut, Lualaba province, Democratic Republic of Congo and named after Jean-Marie Pendeville (1936–2002), a specialist in collecting minerals of Congo. The new mineral occurs as extremely thin blades (up to ∼0.08–0.10 mm in length and only ∼1 μm thick), often forming lichen-like aggregates and crusts. It is associated with kamotoite-(Y), astrocyanite-(Ce) and shabaite-(Nd), uranophane and sklodowskite. Pendevilleite-(Y) crystals are whitish or greyish-white, locally pale-bluish white. The mineral is brittle; has an irregular fracture and a Mohs hardness of ∼2. Cleavage is perfect on {001}. Electron microprobe analyses provided (on the basis of 2 apfu U with CO32–, H2O derived from the structure and OH– to keep the electroneutrality) formula Mg1.78[(Y1.42Gd0.36Dy0.33Nd0.16Er0.14Sm0.13Eu0.12Tb0.05Ho0.04Yb0.04Ce0.03Tm0.03Pr0.01)Σ2.86 Ca0.11Pb0.01]Σ2.98Al0.88(UO2)2(CO3)7(OH)5.02(H2O)16. Pendevilleite-(Y) is triclinic, P$\overline 1 $, a = 11.9130(3) Å, b = 13.5252(11) Å, c = 16.1531(3) Å, α = 107.052(3)°, β = 92.7765(19)°, γ = 109.676(4)° and V = 2311.5(2) Å3 (Z = 2) at 97 K. The crystal structure (dynamical refinement against 3D ED data; R1 = 0.0948 for 1168 [I > 3σ(I)] reflections) possesses a large heteropolyhedral framework based on both a finite [(UO2)(CO3)3]4– cluster (UTC cluster) and a dimeric [(UO2)2(CO3)4(OH)2]6– unit formed due to olation of uranyl polyhedra. There are three M sites in the structure, occupied by Y3+ and Ln3+, with symmetry-related equivalents forming a polyoxometalate cluster of the general composition [(Y,Ln)6(OH)8(H2O)4(CO3)4]2+. Additionally, there is one Al site in the structure (symmetrically related equivalents forming a dimer of composition [Al2O2(OH)8]6–), and two Mg sites in octahedral coordination MgO2(H2O)4. In the sizeable channels of the framework (running parallel to c), there are at least eight independent partially occupied and disordered O sites of the H2O molecules.

Ranunculite is a rare supergene hydrated aluminium uranyl phosphate reliably reported only from the type locality – the Kobokobo pegmatite in the Sud-Kivu province, Democratic Republic of Congo; its structure has remained unknown until now. Based on 3D electron diffraction data, ranunculite is monoclinic, with a C-centred unit cell: a = 11.1812(7) Å, b = 17.9281(5) Å, c = 17.91548(16) Å, β = 98.350(4)°, and V = 3553.2(2) Å3 (Z = 4). The structure (C2/c) was refined kinematically to R1 = 0.4114 for 1697 unique observed reflections. The structure of ranunculite is based upon infinite uranyl-phosphate sheets of novel topology. The two-dimensional representation of the structural unit consists of hexagons (occupied by U6+), pentagons (occupied by U6+), squares (occupied by Al3+) and triangles (occupied by P5+). Those sheets are stacked perpendicular to c; the interplanar distance is ~9.5 Å. They result from the clusters of edge-sharing uranyl hexagonal and pentagonal bipyramids linked by Al-octahedra and PO4 tetrahedra. The decoration of the sheets is unique but somewhat resembles the arrangement (of U-clusters, squares and triangles) observed in bijvoetite and lepersonnite topologies; the ring symbol is 61514232. In the interlayer, there are two Al3+-hosting sites (one [6]- and [5]-coordinated; the pyramidal one is only partially occupied), as well as isolated H2O groups. There is an extensive network of hydrogen bonds; adjacent sheets are either held by hydrogen bonds only or by tetramers of Al-polyhedra when occupied (through shared O19). This arrangement most probably causes a poor crystallinity of ranunculite (which gives rise to stacking faults observed in the powder diffraction data).

The composition of phosgenite (ideal formula Pb2(CO3)Cl2, sp. gr. P4/mbm with a ≈ 8.15 and c ≈ 8.87 Å) from Monteponi Mine, Iglesias, Sardinia, Italy, its crystal structure and its high-T behaviour up to the onset of decomposition were investigated by a series of chemical analytical and diffraction techniques, including single-crystal X-ray (data collected at 293 K) and neutron diffraction (at 293 and 20 K), in situ high-T powder X-ray diffraction (XRD) and thermogravimetric analysis. Concentrations of >65 elements were measured. The empirical mineralogical formula of phosgenite, obtained by the multi-analytical approach used in this study, is almost identical to the ideal one, with only a few elements measured above the detection limit: Σ(Na2O+K2O+CaO+SiO2) = 0.11 wt.%. The concentration of other industrially relevant elements is insignificant. X-ray and neutron refinements, based on data collected at room T, confirm the previously reported general structural model of phosgenite, while providing a full description of the displacement parameters of all the atomic sites. The building unit of the crystal structure of phosgenite is represented by a Pb-polyhedron, in which Pb is coordinated by 5Cl + 4O (coordination number CN = 9), forming a monocapped square antiprism. The combination of face-sharing Pb-polyhedra generates dense layers parallel to (001), which are connected by (edge-sharing) CO3-groups to form the crystalline edifice. Low-T neutron diffraction data show evidence of a temperature-mediated phase transition towards a lower symmetry (space group P$\bar 4$), with a modest distortion of the building units of the structure. A tentative description of the low-T mechanisms, at the atomic scale, that can lead to the phase transition is provided.

The high-T behaviour of phosgenite proves this mineral is stable at least up to 523 K, at which the first evidence of transformation (with the coexistence of phosgenite + Pb2O2Cl, and probably an amorphous phase) takes place. The XRD pattern at 548 K unveils a more complex scenario, with coexisting: phosgenite (dominant) + Pb2O2Cl (minor) + mendipite [Pb3O2Cl2] (minor) + Pb5O2Cl6 (subordinate) (+ amorphous phase). This phase composition is preserved up to 648 K, after which phosgenite is no longer preserved, and the stable compounds are: mendipite [Pb3O2Cl2] (dominant), Pb2O2Cl (subordinate) + Pb5O2Cl6 (subordinate) + kutnohorite-type [Ca(Mn,Mg,Fe2+)(CO3)2] (likely, very minor) (+ amorphous phase). The same assemblage is observed up to 698 and back to 298 K after a decrease in T, showing an irreversible transformation of the pristine material. Therefore, the irreversible temperature-induced degradation of phosgenite is substantially governed by a decarbonation process.

Tennantite-(In), Cu6(Cu5In)As4S13, was approved as a new mineral species from the Pefka epithermal ore deposit, Alexandroupolis, Evros, Western Thrace, Greece. It was identified as anhedral grains, up to 0.1 mm in size, intimately associated with roquesite, galena and tennantite-(Fe) in quartz gangue. In reflected light, tennantite-(In) is isotropic, pale grey in colour. Reflectance values for the four COM wavelengths in air are [λ (nm): R (%)]: 470: 31.2; 546: 30.7; 589: 30.5; 650: 28.8. Electron microprobe analysis gave (in wt.% – average of 7 spot analyses): Cu 43.83(95), Mn 0.22(8), Fe 0.65(46), Zn 0.57(12), Cd 0.16(5), Pb 0.26(2), As 14.38(3.00), In 5.05(59), Sb 7.74(3.08), Te 0.48(9), S 26.18(79), total 99.52(78). The empirical formula of the sample studied, recalculated on the basis of ΣMe = 16 atoms per formula unit, is Cu10.82In0.69Fe0.18Zn0.14Mn0.06Cd0.02Pb0.02As3.01Sb1.00Te0.06S12.81. Tennantite-(In) is cubic, I$\bar 4$3m, with a = 10.285(2) Å, V = 1088.1(6) Å3 and Z = 2. The five strongest reflection lines in the calculated powder X-ray diffraction pattern are [d in Å, (I), hkl]: 2.969, (100), 222; 2.571, (20), 400; 1.878, (7), 521; 1.818, (42), 440; and 1.551, (21), 622. The crystal structure of tennantite-(In) has been refined by single-crystal X-ray diffraction data to a final R1 = 0.0253 on the basis of 240 unique reflections with Fo > 4σ(Fo) and 23 refined parameters. Tennantite-(In) is isotypic with other members of the tetrahedrite group. Indium is hosted at the tetrahedrally coordinated M(1) site, in accord with the known preference of this element for tetrahedrally coordinated bonding environments.

Here we present the first single-crystal X-ray diffraction analysis of zolenskyite, a chromium-bearing sulfide mineral (FeCr2S4) and newly identified polymorph of daubréelite, discovered in the Muonionalusta meteorite, a well-characterized IVA iron meteorite. Zolenskyite occurs as rare micron-scale grains associated closely with daubréelite and stishovite, within a troilite matrix. Chemical analysis confirms a pure, homogeneous FeCr2S4 composition. The crystal structure was refined in the monoclinic C2/m space group, revealing a framework of face-sharing octahedra, consistent with a cation-deficient NiAs-type structure, distinct from the spinel-type structure of daubréelite. Zolenskyite forms under high-pressure (>7 GPa) and high-temperature (>1000 K) conditions, probably through solid-state transformation from daubréelite during shock events. The serendipitous recognition of zolenskyite emphasizes the value of careful micron-scale mineralogical investigations in revealing transient or metastable phases that record otherwise inaccessible physicochemical conditions. These findings contribute to understanding the thermal and shock history of meteorite parent bodies and the stability of Fe–Cr sulfides in extraterrestrial environments.

Fanfaniite, Ca4Mn2+Al4(PO4)6(OH)4·12H2O, from the Hühnerkobel pegmatite mine, Bavaria, has been characterised by chemical analyses and synchrotron single-crystal diffraction. The average crystal structure was refined in space group C2/c (cell parameters a = 10.055(2), b = 24.132(5), c = 6.2590(10) Å, β = 91.35(3)°) to compare with reported monoclinic structures of other calcioferrite-group minerals with general formula Ca4AB4(PO4)6(OH)4·12H2O, A = Mn2+, Fe2+, Mg, B = Al, Fe3+. The average structure contains disordered half-occupied A sites and associated coordinated water molecules. The diffraction data for fanfaniite contains weak reflections that violate the c-glide condition, as also reported for montgomeryite, and in addition contains extremely weak, diffuse reflections requiring a doubling of a, as reported for kingsmountite. Structure refinements were conducted for the noncentrosymmetric C2 model used for montgomeryite and for the P$\bar 1$ model used for kingsmountite. The fanfaniite diffraction data is better explained by the triclinic model with doubled a cell parameter, although the extent of ordering of the A-site cations is considerably lower (56%) than reported for kingsmountite (85%). If the C2 model contributes, it can only be at the scale of the unit cell.

This study reveals the mineralogy and origin of unusual silica-carbonate bodies (listvenite) associated with tectonized serpentinites and Permian–Triassic phyllites from the Tokat region in northern Turkey. The listvenite includes green-coloured opaline silica intersected by saddle dolomite and minor sulfide mineralization (pyrite, cobaltite and enargite). It also hosts abundant chalcedonic bodies, i.e. agate of bluish to bluish-white colour. Listvenite-hosted opaline silica has been recognized as lussatite, a fibrous birefringent opal-CT variety, with a dominantly ‘tridymitic’ structure. The green colouration results from discrete, but widely disseminated, Cr-bearing smectite-group minerals, such as volkonskoite and/or Cr-montmorillonite. Chromium, the main colouring agent as determined by element-distribution mapping and visible-light spectroscopy, was probably derived from spinel-group minerals (e.g. chromite), the relics of which mark the presence of an ultramafic protolith. In contrast, the vein agate is composed of length-fast chalcedony, with subordinate quartzine and minor opaline silica, followed by drusy quartz. Its bluish colour appears to be related to scattering effects enhanced by elevated moganite contents (up to 46 wt.%). The observed mineral paragenesis suggests at least a two-stage evolution: (1) early listvenitization marked by carbonate-silica alteration of the host serpentinite together with concomitant sulfide precipitation; and (2) subsequent silicification producing chalcedony (agate) veins under low-temperature conditions, followed by possible dissolution of the earlier saddle dolomite. This evolution reflects complex fluid–rock interactions involving CO2-rich, Ca-bearing and later Si-rich fluids under fluctuating redox and pH conditions. Hence, the proposed crystallization sequence of the associated mineral assemblage is: sulfides (cobaltite+pyrite+enargite) → saddle dolomite → opal (lussatite) + Cr-smectite → chalcedony (agate). These data provide new insights into the genesis, colouration mechanisms and structural state of Cr-bearing opaline and chalcedonic silica in altered ultramafic terrains.

Erionite is a naturally-occurring zeolite mineral series with a fibrous-asbestiform shape, that has been linked to malignant mesothelioma due to its high biopersistence and respirability. Despite its potential health risks, its occurrence, variability and environmental significance in New Zealand remain poorly understood. This study aims to better understand the occurrence of erionite by investigating its geological settings, crystal chemistry, and morphological variability. A total of 138 samples were initially screened for erionite occurrence, from which three localities were selected for detailed characterisation: Kaipara, Auckland, and Mount Somers, representing erionite-Na, erionite-Ca and erionite-K, respectively. A comprehensive stepwise analytical approach was employed, initially using PXRD and SEM-EDS for phase identification and morphological analysis. Where erionite was identified, further analysis was conducted using TEM-3DED, micro-Raman and EMPA. Results reveal that palaeoenvironmental conditions influence erionite’s crystal habits and composition, occurring as prismatic aggregates, acicular bundles and woolly asbestiform fibres. Many of the fibres met the World Health Organization (WHO) respirability criteria, highlighting potential health risks if airborne. Although bulk concentrations are relatively low, the presence of respirable fibres in both rural and urban settings raises concerns regarding potential environmental exposure during earthworks and construction. This study establishes the link between erionite’s geological setting and morphology. Providing essential data to inform environmental monitoring, land-use planning and risk mitigation in areas where erionite-bearing rocks may be disturbed.

The crystal structure of jungite from the Hagendorf Süd pegmatite, Bavaria, has been determined using synchrotron diffraction data collected at the Australian Synchrotron microfocus beamline MX2.

The mineral has orthorhombic symmetry, space group Aba2, with cell parameters a = 11.995(2), b = 24.692(5) and c = 9.920(2) Å. The structure was refined to wRobs = 0.063 for 3558 reflections with I > 3σ(I). It is built from double heteropolyhedral layers parallel to (010) with [Ca(H2O)6]2+ hydrated cations and H-bonded H2O in the interlayer region. The heteropolyhedral layers comprise seven-member rings of corner-connected ZnO4 and PO4 tetrahedra and Fe3+2O10 dimers of edge-shared octahedra. From the refined structural model the formula is established as [Ca(H2O)6]2Zn4Fe3+8(PO4)8(OH)12(H2O)4·4H2O. The jungite specimen also contains crystals that indexed with triclinic cell parameters, a ≈ 11.95, b = 10.05, c = 9.9 Å, α ≈ 86.7, β =89.9 and γ = 83.4°. They gave poor diffraction due to multiple components with different orientations, but it was possible to extract intensity data for a single component and solve the structure. The model contains identical double heteropolyhedral layers parallel to (010) as in the orthorhombic mineral, but differs in that the Ca atoms are coordinated predominantly to layer anions. The formula obtained from the structural model is [Ca2(H2O)5]Zn4Fe3+8(PO4)8(OH)12(H2O)4·2H2O, corresponding to a dehydrated form of jungite, with a contraction in the layer spacing from 12.35 to 10.0 Å.

The new mineral magganasite, ideally CuFe3+3O(AsO4)3, was found in the Arsenatnaya fumarole at the Second scoria cone of the Northern Breakthrough of the Great Tolbachik Fissure Eruption, Tolbachik volcano, Kamchatka, Russia. It is associated with sanidine, lammerite, paralammerite, johillerite, calciojohillerite, alarsite, hematite, tenorite, cassiterite, langbeinite, euchlorine, fedotovite and wulffite. Magganasite forms prismatic crystals up to 0.2 mm long and up to 0.04 mm thick typically assembled in clusters up to 1 mm across. It is translucent, golden- or red-brown to brownish-yellow, with strong vitreous to semi-metallic lustre. Dcalc is 4.708 g cm–3. In reflected light, magganasite is grey, weakly anisotropic. The reflectance values [Rmax–Rmin,% (λ, nm)] are: 13.1–13.1 (470), 12.5–11.9 (546), 12.2–11.9 (589), 11.9–11.8 (650). Chemical composition (wt.%, electron microprobe data) is: CuO 14.69, ZnO 0.06, Al2O3 0.49, Cr2O3 0.19, Fe2O3 30.62, TiO2 2.22, SiO2 0.21, P2O5 0.12, V2O5 0.10, As2O5 50.72, SO3 0.63, total 100.05. The empirical formula based on 13 O apfu is Cu1.22Al0.06Cr0.02Fe3+2.52Ti0.18(As2.91S0.05Si0.02P0.01V0.01)Σ3.00O13. Magganasite is triclinic, P$\bar 1$, a = 5.1813(7), b = 9.6427(11), c = 9.6834(11) Å, α = 82.066(10), β = 78.680(11), γ = 79.962(10)°, V = 464.41(10) Å3 and Z = 2. The strongest reflections of the PXRD pattern [d,Å(I)(hkl)] are: 3.761(100)(102, 120), 3.540(46)(022), 3.280(88)(1$\bar 1$2), 3.204(62)($\bar 1$20), 3.170(41)($\bar 1$02, 030), 2.989(51)($\bar 1$12), 2.889(65)(103, 130), and 2.510(64)(200). The crystal structure, solved from single-crystal XRD data (R = 0.0609), is unique. It is based on the polyhedral ribbons built by two zig-zag chains of edge-sharing Fe2- and Fe3-centred octahedra linked via dimers of edge-sharing Cu-centred distorted tetragonal pyramids. The neighbouring ribbons are linked via dimers of edge-sharing Fe1-centred octahedra. AsO4 tetrahedra reinforce the linkage between the ribbons. The mineral is named in honour of the Greek mineralogist and petrologist Prof. Dr. Andreas Magganas (born 1954).