Fassinaite, ideally Pb22+(S2O3)(CO3), is a new mineral from the Trentini mine, Mount Naro, Vicenza Province, Veneto, Italy (holotype locality). It is also reported from the Erasmus adit, Schwarzleo District, Leogang, Salzburg, Austria and the Friedrich-Christian mine, Schapbach, Black Forest, Baden-Wurttemberg, Germany (cotype localities). At the Italian type locality it occurs as acicular [010]. colourless crystals up to 200 μn long, closely associated with galena, quartz and anglesite. At the Austrian cotype locality it is associated with cerussite, rare sulphur and very rare phosgenite. At the German cotype locality anglesite is the only associated phase. Fassinaite crystals commonly have flat chisel-shaped terminations. They are transparent with vitreous to adamantine lustre and a white streak. Fassinaite is brittle with an irregular fracture and no discernible cleavage; the estimated Mohs hardness is 11/2—2. The calculated density for the type material is 6.084 g cm–3 (on the basis of the empirical formula), whereas the X-ray density is 5.947 g cm–3. In common with other natural lead thiosulphates (i.e. sidpietersite and steverustite) fassinaite has intense internal reflections, which do not allow satisfactory optical data to be collected; the crystals are length-slow and have very high birefringence. The mineral is not fluorescent.

Fassinaite is orthorhombic, space group Pnma, with unit-cell parameters (for the holotype material) a = 16.320(2), b = 8.7616(6), c = 4.5809(7) Å, V = 655.0(1) Å3, a:b:c = 1.863:1:0.523, Z = 4. Single-crystal structural studies were carried out on crystals from all three localities: R1(F) values range between 0.0353 and 0.0596. The structure consists of rod-like arrangements of Pb-centred polyhedra that extend along the [010] direction. These ‘rods’ are linked, alternately, by (CO3)2– and (S2O3)2– groups. The (S2O3)2– groups point alternately left and right (in a projection on [001] with [010] set vertical) if the apex occupied by the S2– in the thiosulphate group is defined to be the atom giving the direction. The lead atoms are nine-coordinated by seven oxygen atoms and two sulphur (S2–) atoms. The eight strongest X-ray powder-diffraction lines [d in Å (I/I0) (hkl)] are: 4.410 (39) (101), 4.381 (59) (020), 4.080 (62) (400), 3.504 (75) (301), 3.108 (100) (121), 2.986 (82) (420), 2.952 (49) (221) and 2.736 (60) (321). Electron-microprobe analyses produce an empirical formula Pb2.01(1)(S1.82(2)O3)CO3 (on the basis of six oxygen atoms). The presence of both carbonate and thiosulphate groups was corroborated by Raman spectra, which are discussed in detail. Fassinaite is named after Bruno Fassina (b. 1943), an Italian mineral collector who discovered the mineral in 2009.

The type specimen of peisleyite has been reinvestigated by a combination of scanning electron microscopy, electron probe microanalysis (EPMA) and synchrotron powder X-ray diffraction. Morphological investigation showed that mats of peisleyite crystals, individually <3 μm across, are intergrown with wavellite veinlets to form the white cryptocrystalline material that is typical of ‘peisleyite’. New EPMA data (mean of 12 analyses) gave the empirical formula of peisleyite as (Na1.69Ca0.18)Σ1.87(Al9.04Fe0.03)Σ9.07[(P6.28S1.38Si0.25)O4]Σ7.91(OH)6.66·27.73H2O, or ideally Na2Al9[(P,S)O4]8(OH)6·28H2O. The associated wavellite was found to be F-rich. Synchrotron powder data were indexed and refined and gave the following unit cell: P1̄, a = 9.280(19), b = 11.976(19), c = 13.250(18) Å, α = 91.3(1), β = 75.6(1), γ = 67.67(1)°, V = 1308(5) Å3 and Z = 4. These data are significantly different to those reported in the original description of peisleyite.

Bêhounekite, orthorhombic U(SO4)2(H2O)4, is the first natural sulphate of U4+. It was found in the Geschieber vein, Jáchymov (St Joachimsthal) ore district, Western Bohemia, Czech Republic, crystallized on the altered surface of arsenic and associated with kaatialaite, arsenolite, claudetite, unnamed phase UM1997-20-AsO:HU and gypsum. Bêhounekite most commonly forms short-prismatic to tabular green crystals, rarely up to 0.5 mm long. The crystals have a strong vitreous lustre and a grey to greenish grey streak. They are brittle with an uneven fracture and have very good cleavage along ﹛100﹜. The Mohs hardness is about 2. The mineral is not fluorescent either in short- or long-wavelength UV radiation. Bêhounekite is moderately pleochroic, α∼β is pale emerald green and γ is emerald green, and is optically biaxial (+) with α = 1.590(2), β = 1.618(4), γ = 1.659(2) (590 nm), 2V (calc.) = 81°, birefringence 0.069. The empirical formula of bêhounekite (based on 12 O atoms, from an average of five point analyses) is (U0.99Y0.03)Σ1.02(SO4)1.97(H2O)4. The simplified formula is U(SO4)2(H2O)4, which requires UO2 53.77. SO3 31.88, H2O 14.35, total 100.00 wt.%. Bêhounekite is orthorhombic, space group Pnma, a = 14.6464(3), b = 11.0786(3), c = 5.6910(14) Å, V = 923.43(4) Å3, Z = 4, Dcalc = 3.62 g cm–3. The seven strongest diffraction peaks in the X-ray powder diffraction pattern are [dobs in Å (I) (hid)]: 7.330 (100) (200), 6.112 (54) (210), 5.538 (21) (020), 4.787 (42) (111), 3.663 (17) (400), 3.478 (20) (410), 3.080 (41) (321). The crystal structure of bêhounekite has been solved by the charge-flipping method from single-crystal X-ray diffraction data and refined to R1 = 2.10 % with a GOF = 1.51, based on 912 unique observed diffractions. The crystal structure consists of layers built up from [8]-coordinate uranium atoms and sulphate tetrahedra. The eight ligands include four oxygen atoms from the sulphate groups and four oxygen atoms from the H2O molecules. Each uranium coordination polyhedron is connected via sulphate tetrahedra with other uranium polyhedra and through hydrogen bonds to the apices of sulphate tetrahedra. The dominant features of the Raman and infrared spectra of bêhounekite are related to stretching vibrations of SO4 tetrahedra (∼1200–950 cm–1), O-H stretching modes (∼3400–3000 cm–1) and H—O—H bending modes (∼1650 cm–1). The mineral is named in honour of František Bêhounek, a well known Czech nuclear physicist.

Rinkite, ideally Na2Ca4REETi(Si2O7)2OF3, is a common mineral in alkaline and peralkaline rocks. The crystal structures of five rinkite crystals from three alkaline massifs: Ilimaussaq, Greenland; Khibiny, Kola Peninsula, Russia and Mont Saint-Hilaire, Canada, have been refined as two components related by the TWIN matrix (–1 0 0, 0 –1 0, 1 0 1) (Mo-αa radiation). The crystals, a = 7.4132-7.4414, b = 5.6595-5.6816, c = 18.8181-18.9431 Å, β = 101.353-101.424(2)°, V= 776.1-786.7 Å3, space group P21lc, Z = 2, Dcalc = 3.376—3.502 g cm–3, were analysed using an electron microprobe subsequent to collection of the X-ray intensity data. Transmission electron microscopy confirmed the presence of pseudomerohedral twinning in rinkite crystals. The crystal structure of rinkite is a framework of TS (titanium silicate) blocks. The TS block consists of HOH sheets (H-heteropolyhedral, O-octahedral). The TS block in rinkite exhibits linkage and stereochemistry typical for Group I (Ti = 1 a.p.f.u.) of Ti disilicate minerals: two H sheets connect to the O sheet such that two (Si2O7) groups link to the trans edges of a Na polyhedron of the O sheet. The crystal chemistry of rinkite and nacareniobsite-(Ce) is discussed.

Monoclinic, non-stoichiometric natrojarosite—hydroniumjarosite solid solution phases have been synthesized hydrothermally over a range of temperatures, starting compositions and reaction times, and have been characterized using Rietveld refinement of synchrotron X-ray diffraction data, and chemical and thermal analyses. The H atom locations have been obtained from refinement of neutron diffraction data on a deuterated sample. The results confirm a direct relationship between the monoclinic distortion and the ordering of iron site vacancies in one of two independent iron sites. Ordering of iron vacancies gives rise to domains containing butlerite-like 7 Å chains of corner-connected octahedra and tetrahedra. The formation of these chains within (100) planes results in an expansion of the monoclinic a lattice parameter and a contraction of the c parameter relative to stoichiometric jarosites. The results support a recent model for iron deficiency, whereby an iron vacancy is compensated by the replacement of four coordinated OH– ions by H2O molecules, with one of the H2O molecules coming from deprotonation of H3O+. The general formula, based on intergrowth of stoichiometric jarosite and non-stoichiometric, butlerite-like regions, is [(Na,H3O)Fe3(SO4)2(OH)6]1–y[(H2O)Fe2(SO4)2(OH)2(H2O)4]y.

A lenticular metagabbro crops out in an early Palaeozoic metasedimentary sequence at Nurra, northwest Sardinia. The metagabbro consists of variable proportions of early-formed coarse-grained albite, chlorite, epidote and apatite, later biotite and amphibole, and late stilpnomelane. Clinopyroxene and ilmenite are rare relict igneous minerals; albite has completely replaced primary plagioclase.

The metamorphic evolution of the Nurra metagabbro has been investigated by pseudosection modelling for a fixed bulk-rock composition in the Na2O—CaO—K2O—FeO—MgO—A12O3—SiO2—H2O (NCKFMASH) model system with added Ti and Mn in the P-T range 1-11 kbar and 150-450°C. The P—T path of the metagabbro is a loop with a prograde segment overprinted by later metamorphic re-equilibration. The pressure peak was at ⩽7 kbar and ∼400°C. The subsequent temperature peak, at ∼440°C, was accompanied by a decrease in pressure to ∼3 kbar. The final P—T evolution of the metagabbro is characterized by near-isobaric cooling to 250—300°C, with the formation of stilpnomelane. The P—T path of the Nurra gabbro is typical of continental orogenic belts that have undergone crustal thickening.

Cerianite-(Ce), ideally CeO2, occurs as rounded grains up to 5 μm across in a block of highly altered calcite carbonatite lava from the Kerimasi volcano, and as euhedral crystals up to 200 μm across in carbonatite-derived eluvial deposits in the Kisete and Loluni explosion craters in the Gregory Rift, northern Tanzania. X-ray powder diffraction data (a = 5.434(5) Å) and Raman spectroscopy (minor vibration modes at 184 and 571 cm—1 in addition to a strong signal at 449 cm—1) suggest the presence of essential amounts of large cations and oxygen vacancies in the Kisete material. Microprobe analyses reveal that the mineral contains both light and heavy trivalent rare earth elements (REE) (7.9-15.5 wt.% LREE2O3 and 4.9-9.7 wt.% HREE2O3), and that it is enriched in yttrium (7.1 — 14.5 wt.% Y2O3) and fluorine (2.2—3.5 wt.%). Single-crystal structure refinement of the mineral confirms a fluorite-type structure with a cation—anion distance of 2.3471(6) Å. The cerianite-(Ce) is considered to be a late-stage secondary mineral in the carbonatitic rocks.

The crystal structure of the manganese phosphate mineral gatehouseite, ideally Mn52+(PO4)2(OH)4, space group P212121, a = 17.9733(18), b = 5.6916(11), c = 9.130(4) Å, V= 933.9(4) Å3, Z = 4, has been solved by direct methods and refined from single-crystal X-ray diffraction data (T = 293 K) to an R index of 3.76%. Gatehouseite is isostructural with arsenoclasite and with synthetic Mn52+(PO4)2(OH)4. The structure contains five octahedrally coordinated Mn sites, occupied by Mn plus very minor Mg with observed <Mn—O> distances from 2.163 to 2.239 Å. Two tetrahedrally coordinated P sites, occupied by P, Si and As, have <P—O> distances of 1.559 and 1.558 Å. The structure comprises two types of building unit. A strip of edge-sharing Mn(O,OH)6 octahedra, alternately one and two octahedra wide, extends along [010]. Chains of edge- and corner-shared Mn(O,OH)6 octahedra coupled by PO4 tetrahedra extend along [010]. By sharing octahedron and tetrahedron corners, these two units form a dense three-dimensional framework, which is further strengthened by weak hydrogen bonding. Chemical analyses by electron microprobe gave a unit formula of (Mn4.99Mg0.02)Σ5.01(P1.76Si0.07(As0.07)Σ2.03O8(OH)3.97.

Charoite, ideally (K,Sr,Ba,Mn)15–16(Ca,Na)32[(Si70(O,OH)180)](OH,F)4·nH20, is a rock-forming mineral from the Murun massif in Yakutia, Sakha Republic, Siberia, Russia, where it occurs in a unique alkaline intrusion. Charoite occurs as four different polytypes, which are commonly intergrown in nanocrystallme fibres. We report the structure of charoite-96 (a = 32.11(6), b = 19.77(4), c = 7.23(1) Å, β = 95.85(9)°, V = 4565(24) Å3, space group P21/m), which was solved ab initio by direct methods on the basis of 2676 unique electron diffraction reflections collected by automated diffraction tomography and refined to R1/wR2 = 0.34/0.37. The structure of charoite-96 is related to that of the charoite-90, which was also solved recently. Both structures are composed of three different types of dreier silicate chains running along [001] and separated by ribbons of edge-sharing Ca- and Na-centred octahedra. In the structure of charoite-96, adjacent blocks formed by three different silicate chains and stacked along the x axis, are shifted by a translation of 1/2 c. The shifts involve a hybrid dreier quadruple chain, [Si17O43]18– and a double dreier chain, [Si6O17]10–. In charoite-90 adjacent blocks are stacked without shifts.

Cossaite, ideally (Mg0.5,☐)Al6(SO4)6(HSO4)F6·36H20, was found in the altered pyroclastic breccia of an active fumarole (T about 350°C) located at the rim of the La Fossa crater, Vulcano Island, Aeolian archipelago, Sicily, Italy. Cossaite is trigonal, space group R3̄, with a = 22.010(2), c = 9.238(1) Å, V = 3875.6(6) Å3, Z = 3. It forms stout prismatic hexagonal crystals up to 100 μm in size, terminated by rhombohedral faces, and is associated with thermessaite, vlodavetsite, sassolite and salammoniac. Cossaite is colourless to white, the streak is white and the lustre vitreous. It is not fluorescent in either long-wave or short-wave ultraviolet radiation. The calculated density is 2.075 g cm–3. The mean refractive index nobs is 1.49(1) (589 nm). Chemical analysis gave MgO 1.4, A12O3 19.5, SO3 34.7, F 5.7, (H2O 40.85, from structure refinement), O=F –2.4, total 99.75 wt.%, corresponding to the empirical formula Mg0.56Al6.19S7.01H73.37F4.85O65.15 calculated on the basis of 70 oxygen plus fluorine atoms. The strongest six lines in the X-ray powder diffraction pattern [dobs(Å) (I) (hkl)] are: 4.15 (100) (140), 3.87 (70) (32̄2), 11.00 (50) (110), 4.58 (25) (131), 2.770 (20) (3̄33), 2.166 (20) (1̄8̄1). The crystal structure was refined to a final R index of 0.0349. It contains octahedral [A1(H2O)5F]2+ cations and sulphate anions interacting via hydrogen bonds to form channels running along [001], where disordered [Mg(H2O)6]2+ cations and hydrogensulphate anions are hosted.

The new mineral anorpiment, As2S3, the triclinic dimorph of orpiment, has space group PI and cell parameters a = 5.7577(2), b = 8.7169(3), c = 10.2682(7) Å, α = 78.152(7), β = 75.817(7), γ = 89.861(6)°, V = 488.38(4) Å3 and Z = 4. It occurs at the Palomo mine, Castrovirreyna Province. Huancavelica Department, Peru. It is a low-temperature hydrothermal mineral associated with dufrenoysite, muscovite, orpiment, pyrite and realgar. It occurs in drusy crusts of wedge-shaped, transparent, greenish yellow crystals. The streak is yellow. The lustre is resinous on crystal faces, but pearly on cleavage surfaces. The Mohs hardness is about VA. The mineral is sectile with an irregular fracture and one perfect and easy cleavage on ﹛001﹜. The measured and calculated densities are 3.33 and 3.321 g cm–3, respectively. All indices of refraction are greater than 2. The mineral is optically biaxial (—) with 2V = 35—40° and no observed dispersion. The acute bisectrix (X) is approximately perpendicular to the ﹛001﹜ cleavage. Electron microprobe analyses yielded the averages and ranges in wt.%: As 58.21 (57.74–59.03), S 38.72 (38.33–39.00), total 96.94 (96.07–97.75), providing the empirical formula (based on 5 atoms) As1.96S3.04. The strongest powder X-ray diffraction lines are [d (hkl) I] 4.867(002) 97, 4.519 (110,11̄1) 77, 3.702 (1̄1̄1) 46, 3.609 (022,11̄2) 82, 2.880(201,02̄2,1̄2̄1,023) 75, 2.552 (1̄13,1̄31,132) 100, 2.469 (114,130,13̄1) 96. The structure of anorpiment [R1 = 0.021 for 1484 reflections with F0 > 4σ(F)] consists of layers of covalently bonded As and S atoms. Each S atom bonds to two As atoms at As—S—As angles between 100.45 and 104.15°. Each As atom is strongly bonded to three S atoms at S—As—S angles between 91.28 and 103.59°, forming an AsS3 pyramid with As at its apex. The As—S linkages within the layers form rings of six AsS3 pyramids. Interlayer bonding forces are interpreted as van der Waals. The structure of anorpiment is similar to that of orpiment in that it is composed of layers of As2S3 macromolecules, but arranged in a different stacking sequence.

Haláp Hill is an eroded remnant of young (∼3 Ma) alkaline basalt in the western part of the Bakony–Balaton Highland Volcanic Field, Tapolca, Hungary. Cavities in the basalt contain miarolitic minerals (augite, apatite, magnetite, plagioclase and sanidine), zeolites (analcime, chabazite-Ca, chabazite-Na, garronite, gismondine, gmelinite-Ca, gmelinite-Na, gobbinsite, gonnardite-Na, natrolite, mesolite, phillipsite-Ca, phillipsite-K, phillipsite-Na and scolecite) and other secondary minerals (calcite, smectite-group minerals, goethite and Mn-oxides). Chabazite-Na, gmelinite-Ca, gonnardite-Na, phillipsite-Na and phillipsite-K are reported from Haláp Hill for the first time. The Ca-rich and Na-rich zeolites and abundant calcite were produced by hydrothermal alteration. Mineral assemblages were characterized by X-ray diffraction, differential thermal analysis, energy-dispersive spectrometry and wavelength-dispersive spectrometry. The secondary mineral assemblages were probably formed as a result of low-temperature hydrothermal activity at 50—100°C. Miarolitic minerals crystallized first in cavities in the basalt; they were followed by zeolite-group minerals and calcite. Analcime and phillipsite with or without chabazite/gmelinite/garronite or gobbinsite were the first zeolite-group minerals to crystallize; gonnardite-Na and natrolite crystallized later from Na-rich fluids. Calcite and smectite-group minerals crystallized continually. This paragenetic sequence is similar to others which have been reported in basalt from other localities in the Balaton Highland, Iceland and Northern Ireland.