Leisingite, ideally Cu(Mg,Cu,Fe,Zn)2Te6+O6·6H2O, is hexagonal, P3 (143), with unit-cell parameters refined from powder data: a = 5.305(1), c = 9.693(6) Å, V = 236.2(2) Å3, c/a = 1.8271, Z = 1. The strongest six reflections of the X-ray powder-diffraction pattern [d in Å (I) (hkl)] are: 9.70 (100) (001), 4.834 (80) (002), 4.604 (60) (100), 2.655 (60) (110), 2.556 (70) (111) and 2.326 (70) (112). The mineral is found on the dumps of the Centennial Eureka mine, Juab County, Utah U.S.A. where it occurs as isolated, or rarely as clusters of, hexagonal-shaped very thin plates or foliated masses in small vugs of crumbly to drusy white to colourless quartz. Associated minerals are jensenite, cesbronite and hematite. Individual crystals are subhedral to euhedral and average less than 0.1 mm in size. Cleavage {001} perfect. Forms are: {001} major; {100}, {110} minute. The mineral is transparent to somewhat translucent, pale yellow to pale orange-yellow, with a pale yellow streak and an uneven fracture. Leisingite is vitreous with a somewhat satiny to frosted appearance, brittle to somewhat flexible and nonfluorescent; H(Mohs) 3–4; D(calc.) 3.41 for the idealized formula; uniaxial negative, ω = 1.803(3), ɛ = 1.581 (calc.). Averaged electron-microprobe analyses yielded CuO 24.71, FeO 6.86, MgO 6.19, ZnO 0.45, TeO3 36.94, H2O (calc.) [21.55], total [96.70] wt.%, leading to the empirical formula based on O = 12. The infrared absorption spectrum shows definite bands for structural H2O with an O-H stretching frequency centered at 3253 cm−1 and a H-O-H flexing frequency centered at 1670 cm−l. The mineral name honours Joseph F. Leising, Reno, Nevada, who helped collect the discovery specimens.

Four polymorphs of Zn(OH)2 have now been recorded from an oxidised vein exposure near Milltown, Ashover, Derbyshire; sweetite, wülfingite, γ-Zn(OH)2, and ashoverite. The last is a new mineral, a tetragonal modification of Zn(OH)2 containing minor quantities of Pb, Cd and Ca. Its unit cell dimensions are a 6.825(2) and c 33.36(4) Å, giving V = 1554 Å3; Z = 32; space group I41/amd, I41md, or I4¯2d; Dmeas. 3.3, Dcalc 3.44 g cm−3. Ashoverite occurs as colourless platy crystals associated with fluorite; it is uniaxial positive with ω 1.629(2), ε 1.639(2). The chemical composition of sweetite is compared with that of ashoverite.

Structural modifications as a function of the degree of order (Q) in FeTa2O6 ferrotapiolite have been characterized by means of single-crystal X-ray diffraction (SC-XRD). A total of 26 datasets covering the range of Q between 0.154 and 1 have been obtained by thermal treatments followed by quenching of natural tapiolite crystals. Ordering of Fe2+ at the A sites and of Ta5+ at the B sites causes a linear increase in the a/c lattice constants ratio, as a consequence of a linear decrease of the c dimension and only slight modifications of the a parameter. Calibration of a/c vs. Q represents a very useful tool for a rapid determination of the degree of order of tapiolite samples. Polyhedral volumes of the two octahedral sites vary linearly with Q as a consequence of the different ionic radii of the two species. Both the sites remain almost regular at all Q values but the B site shows an increasing off-centre displacement of the cation with increasing Q. Observed structure factors of supercell reflections, characterized by l ≠ 3n, increase linearly as a function of Q, thus representing a further tool for a quick evaluation of the degree of order.

Ferribushmakinite (IMA2014-055), Pb2Fe3+(PO4)(VO4)(OH), the Fe3+ analogue of bushmakinite, is a new mineral from the Silver Coin mine, Valmy, Iron Point district, Humboldt County, Nevada, USA, where it occurs as a low-temperature secondary mineral in association with plumbogummite, mottramite, Br-rich chlorargyrite and baryte on massive quartz. Ferribushmakinite forms yellow slightly flattened prisms up to 0.2 mm long growing in X and sixling twins. The streak is pale yellow. Crystals are translucent and have adamantine lustre. The Mohs hardness is ∼2, the tenacity is brittle, the fracture is irregular to splintery and crystals exhibit one or two fair cleavages in the [010] zone. The calculated density is 6.154 g/cm3. Electron microprobe analyses provided: PbO 63.69, CaO 0.07, CuO 1.11, Fe2O3 7.63, Al2O3 1.63, V2O5 12.65, As2O5 3.09, P2O58.63, H2O 1.50 (structure), total 100.00 wt.% (normalized). The empirical formula (based on nine O a.p.f.u.) is: (Pb1.99Ca0.01)Σ2.00(Fe0.66Al0.22Cu0.10)Σ0.98(V0.97P0.85As0.19)Σ2.01O7.84(OH)1.16. Ferribushmakinite is monoclinic, P21/m, a = 7.7719(10), b = 5.9060(7), c = 8.7929(12) Å, β = 111.604(8)°, V = 375.24(9) Å3 and Z = 2. The eight strongest lines in the powder X-ray diffraction pattern are [dobs in Å (I)(hkl)]: 4.794(46)(011); 3.245(84)(211); 2.947(100)(020,212,103); 2.743(49)(112); 2.288(30)(220); 1.8532(27)(314,403); 1.8084(27)(multiple); and 1.7204(28)(312,114,321). Ferribushmakinite is a member of the brackebuschite supergroup. Its structure (R1 = 3.83% for 577 Fo > 4σF) differs from that of bushmakinite only in the dominance of Fe3+ over Al in the octahedral site.

'Clinobarylite', BaBe2Si2O7, was defined as a monoclinic dimorph of orthorhombic barylite. Subsequently, its crystal structure was also proved to be orthorhombic, differing from barylite in terms of the space group symmetry, Pmn21 instead of Pmnb, and in unit-cell dimensions. Through the order-disorder (OD) theory, the polytypic relationships between 'clinobarylite' and barylite are described. 'Clinobarylite' corresponds to the MDO1 polytype, with unit-cell parameters a = 11.650, b = 4.922, c = 4.674 Å, space group Pmn21; barylite corresponds to the MDO2 polytype, with a = 11.67, b = 9.82, c = 4.69 Å, space group Pmnb. The re-examination of the holotype specimen of 'clinobarylite' confirmed its orthorhombic symmetry. Its crystal structure has been refined starting from the atomic coordinates calculated for the MDO1 polytype and the refinement converged to R1 = 0.0144 for 929 observed reflections [Fo > 4σFo]. Owing to their polytypic relationships, 'clinobarylite' and barylite should be conveniently indicated as barylite-1O and barylite-2O, respectively; the name 'clinobarylite' should be discontinued. This new nomenclature of the barylite polytypes has been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association (IMA 13-E).

Small crystals of babingtonite and rare sphene occur in a coarse-grained aggregate of fluorapophyllite, stilbite, and calcite, infilling a late-stage cavity in granodiorite from Harcourt, Victoria. This is the first reported occurrence of babingtonite in Victoria. The assemblage crystallized from fluids in which Ca and F were significant and under P–T conditions of the order of 0.5 kbar, 100–150°C. Some of the fluorapophyllite has been altered to opaline silica suggesting that the residual solutions were acidic.

DBE TECHNOLOGY, BGR and GRS are developing a methodology to demonstrate the safety of a repository for high-level waste and spent fuel (HLW/SF) in clays according to the requirements of the German regulating body. In particular, these requirements prescribe that the barrier effect of host rocks must not be compromised by a thermal impact resulting from HLW/SF emplacement. To substantiate and quantify this requirement, we carried out a literature survey of research on thermally-induced changes on clay properties. Effects thus compiled can be divided into thermo-hydro-mechanical and chemical-biological-mineralogical effects and were analysed with regard to their relevance to the integrity of clay host rocks. This analysis identified one effect of major influence within each group: thermal expansion and compaction as well as results of microbial activities. Importantly, it further revealed that a moderate temperature increase above 100°C cannot be expected to compromise the integrity of the geological barrier according to the current knowledge state. Evidence is presented in this paper that temperature increases up to 150°C can actually contribute to an improved performance of a radioactive waste repository by increasing the consolidation of the clay and sterilizing the repository's near-field to depress the deteriorative microbial effects. A quantitative temperature criterion for thermal impact of HLW/SF on clay host rocks is accordingly proposed.

This species, a hydrous zinc phosphate, Zn3P2O8.4H2O, dimorphous with hopeite, was first described by Spencer in 1907. While the material then available was suitable for the physical and chemical description of the new mineral, it did not permit a full crystallographic investigation. Spencer noted that the crystals resembled in a general way those of hemimorphite, and made sufficient measurements to indicate the triclinic character of the mineral. In his sketch of a crystal he indicates that the mineral is twinned, and that this twinning is best seen on the perfect cleavage which is parallel to the brachypinacoid.

Five members of the linnaeite series of sulphides linnaeite Co3S4, siegenite (Co, Ni)3S4, carrollite Co2CuS4, violarite Ni2FeS4, and polydymite Ni3S4 occur in nickel-sulphide-mineralized rocks in areas adjacent to the Kambalda and Scotia deposits of the Kalgoorlie district, Western Australia. Linnaeite, siegenite, carrollite, and polydymite occur in trace amounts as disseminated grains and veinlets. Violarite is also found as disseminations but its major occurrence is in the supergene enriched zones of the ore deposits. Aspects of their mineralogy, including mode of occurrence, general mineragraphy, reflectance at 546 nm, 589 nm and 644 nm, microhardness, and electron probe microanalyses are described.

The new mineral percleveite-(La) (IMA2019–037), ideally La2Si2O7, was found in polymineralic nodules of the Mochalin Log REE deposit, Chelyabinsk Oblast, South Urals, Russia. It is associated with allanite-(Ce), allanite-(La), bastnäsite-(Ce), bastnäsite-(La), ferriallanite-(Ce), ferriallanite-(La), ferriperbøeite-(Ce), ferriperbøeite-(La), fluorbritholite-(Ce), hydroxylbastnäsite-(Ce), perbøeite-(Ce), perbøeite-(La), törnebohmite-(Ce) and törnebohmite-(La). Percleveite-(La) occurs as isolated anhedral grains commonly up to 0.2 mm × 0.4 mm and very rarely up to 1 mm × 1 mm. The new mineral is transparent with greasy lustre. The mineral is very pale yellow to colourless in thin fragments to light yellow in aggregates. It is brittle, with imperfect {001} cleavage and an uneven fracture. Mohs’ hardness is ca. 6. Dcalc = 5.094 g cm–3. Under the microscope, percleveite-(La) is non-pleochroic, optically uniaxial (+), ω = 1.825(10) and ɛ = 1.835(10). The Raman spectrum is given. Chemical data (wt.%, electron-microprobe) are: La2O3 36.80, Ce2O3 31.22, Pr2O3 1.57, Nd2O3 2.96, SiO2 26.73, total 99.28. The empirical formula based on 7 O apfu is (La1.02Ce0.86Nd0.08Pr0.04)Σ2.00Si2.00O7. Percleveite-(La) is tetragonal, P41; the unit-cell parameters are: a = 6.8482(3), c = 24.8550(13) Å, V = 1165.64(11) Å3 and Z = 8. The strongest reflections in the powder X-ray diffraction pattern [d, Å(I)(hkl)] are: 4.194(18)(113), 3.564(16)(106), 3.349(16)(201,202), 3.157(100)(203,116,008), 3.043(22)(211), 2.934(39)(122), 2.893(29)(213) and 2.864(21)(117). The crystal structure of percleveite-(La) is solved from the single-crystal X-ray diffraction data [R = 0.0617 for 2831 unique reflections with I > 2σ(I)]. The new mineral is named as an analogue of percleveite-(Ce) with La predominance over the rare-earth elements.

Three polymorphs of tridymite (MC, PO-10 and MX) have been examined by transmission electron microscopy (TEM), in crystals which also contain lamellae of cristobalite. MX is the least common, and is highly unstable in the electron beam. It occurs as small regions (< 1 µm2) in PO-10 tridymite and at MC/PO-10 boundaries; these regions are interpreted as being strained. A consistent association between PO-10 and the cristobalite lamellae is attributed to the fact that PO-10 can more closely match the low-cristobalite structure than MC can, at boundaries parallel to the plane in which the crystal structures contain layers of SiO4 tetrahedra. An analogous interpretation explains the observation that twin boundaries (associated with 60° or 120° rotation of the layer) are commonly parallel to the layer plane in PO-10 but at high angles to it in MC. Abundant lamellar features, parallel to the same plane in PO-10, are tentatively interpreted as representing twinning by reflection and 180° rotation, which may also account for c* streaking in diffraction patterns.

Flurlite, ideally Zn3Mn2+Fe3+(PO4)3(OH)2·9H2O, is a new mineral from the Hagendorf-Süd pegmatite, Hagendorf, Oberpfalz, Bavaria, Germany. Flurlite occurs as ultrathin (<1 μm) translucent platelets that form characteristic twisted accordion-like aggregates. The colour varies from bright orange red to dark maroon red. Cleavage is perfect parallel to (001). The mineral occurs on mitridatite and is closely associated with plimerite. Other associated minerals are beraunite, schoonerite, parascholzite, robertsite and altered phosphophyllite. The calculated density of flurlite is 2.84 g cm–3. It is optically biaxial (–), α = 1.60(1), β= 1.65(1) and γ = 1.68(1), with weak dispersion and parallel extinction, X ≈ c, Y ≈ a, Z ≈ b. Pleochroism is weak, with colours: X = pale yellow, Y = pale orange, Z = orange brown. Electron microprobe analyses (average of seven) with FeO and Fe2O3 apportioned and H2O calculated on structural grounds, gave ZnO 25.4, MnO 5.28, MgO 0.52, FeO 7.40, Fe2O3 10.3, P2O5 27.2, H2O 23.1, total 99.2 wt.%. The empirical formula, based on 3 P a.p.f.u. is Zn2.5Mn2+0.6Fe2+0.8Mg0.1Fe3+(PO4)3(OH)2·9H2O. Flurlite is monoclinic, P21/m, with the unit-cell parameters (at 100 K) of a = 6.3710(13), b = 11.020(2), c = 13.016(3) Å, β = 99.34 (3)°. The strongest lines in the X-ray powder diffraction pattern are [dobs in Å(I) (hkl)] 12.900(100)(001); 8.375(10)(011); 6.072(14)(101); 5.567(8)(012); 4.297(21)(003); 2.763(35)(040). Flurlite (R1 = 0.057 for 995 F > 4σ(F)) has a heteropolyhedral layer structure, with layers parallel to (001) and with water molecules packing between the layers. The slab-like layers contain two types of polyhedral chains running parallel to [100]: (a) chains of edge-sharing octahedra containing predominantly Zn and (b) chains in which Fe3+-centred octahedra share their apices with dimers comprising Zn-centred trigonal bipyramids sharing an edge with PO4 tetrahedra. The two types of chains are interconnected by corner-sharing along [010]. A second type of PO4 tetrahedron connects the chains to MnO2(H2O)4 octahedra along [010] to complete the structure of the (001) slabs. Flurlite has the same stoichiometry as schoonerite, but with dominant Zn rather than Fe2+ in the edge-shared chains. Schoonerite has a similar heteropolyhedral layer structure with the same layer dimensions 6.4 × 11.1 Å. The different symmetry (orthorhombic, Pmab) for schoonerite reflects a different topology of the layers.

Alcaparrosaite, ideally K3Ti4+Fe3+(SO4)4O(H2O)2, is a new mineral from the Alcaparrosa mine, Cerritos Bayos, El Loa Province, Antofagasta, Chile (IMA2011-024). The mineral occurs on and intergrown with coquimbite, and is also associated with ferrinatrite, krausite, pertlikite, pyrite, tamarugite and voltaite. It is a relatively early phase which forms during the oxidation of pyritic masses under increasingly arid conditions. Alcaparrosaite crystallizes from hyperacidic solutions in a chemical environment that is consistent with its association with coquimbite. It occurs as pale yellow blades and tapering prisms up to 4 mm in length, flattened on {010} and elongated along [100]. The observed crystal forms are {010}, {110}, {1.13.0} and {021}. The mineral is transparent and has a white streak, vitreous lustre, Mohs hardness of about 4, brittle tenacity, conchoidal fracture and no cleavage. The measured and calculated densities are 2.80(3) and 2.807 g cm–3, respectively. It is optically biaxial (+) with α = 1.643(1), β = 1.655(1), γ = 1.680(1) (white light), 2Vmeas = 70(2)° and 2Vcalc = 70.3°. The mineral exhibits strong parallel dispersion, r < v. The optical orientation is X = b; Y^c = 27° in the obtuse angle β. No pleochroism was observed. Electron-microprobe analyses (average of 4) provided: Na2O 0.32, K2O 20.44, Fe2O3 11.58, TiO2 11.77, P2O50.55, SO347.52, H2O 5.79 (calc); total 97.97 wt.%. The empirical formula (based on 19 O) is (K2.89Na0.07)Σ2.96Ti0.984+Fe0.973+(S0.99P0.01O4)4O0.72(OH)0.28(H2O)2. The mineral is hydrophobic, insoluble in cold and hot water, very slowly soluble in acids and decomposes slowly in bases. Alcaparrosaite is monoclinic, C2/c, with the cell parameters a = 7.55943(14), b = 16.7923(3), c = 12.1783(9) Å, β = 94.076(7)°, V = 1542.01(12) Å3 and Z = 4. The eight strongest lines in the X-ray powder diffraction pattern [dobs in A ˚ (Irel) (hkl)] are 6.907 (41) (021,110); 3.628 (34) (023,13); 3.320 (32) (02); 3.096 (100) (202,33,150); 3.000 (40) (51); 2.704 (38) (23,152); 1.9283 (30) (55); 1.8406 (31) (53,06). In the structure of alcaparrosaite (R1 = 2.57% for 1725 Fo > 4σF), Ti4+ and Fe3+, in roughly equal amounts, occupy the same octahedrally coordinated site. Octahedra are linked into dimers by corner sharing. The SO4 tetrahedra link the dimers into chains parallel to [001] and link the chains into undulating sheets parallel to {010}. The sheets link via 10- and 11-coordinated K atoms in the interlayer region. The structure shares some features with that of goldichite.

Concentration, conductivity, temperature, and flow logs from sixteen brine-filled shafts in northern Germany have shown that the brines in all former potash salt mines exhibit a very sharp stratification into lower Mg-rich brine, an upper layer of Na-rich brine, and groundwater at the top. Laboratory experiments have shown that, at the MgCl2-brine/NaCl-brine boundary, both solutions become oversaturated with regard to NaCl, due to diffusion processes. NaCl therefore crystallizes from the solutions and forms a salt plug in the boundary region, which considerably reduces further diffusion. It is concluded that the observed effects would also take place in shafts. The backfilling material helps to nucleate the halite crystals and provides a structure on which they might be supported. The results of these experiments show that the density boundaries in the brine bodies act as barriers against transport of matter while the formation of a halite plug growing independently at the MgCl2/NaCl-brine interface acts as an additional barrier.

Angastonite, ideally CaMgAl2(PO4)2(OH)4-7H2O, is a newly defined mineral from the Penrice marble quarry, South Australia. The mineral occurs as snow-white crusts and coatings up to ∼1 mm thick associated with minyulite, perhamite, crandallite and apatite-(CaF). The streak is white, the lustre is pearly and the estimated hardness is 2 on the Mohs scale. Angastonite forms platy crystals with the forms {010} (prominent), {101}, {101} and {100} (rare), and also occurs as replacements of an unknown pre-existing mineral. There is one cleavage direction on ﹛010} and no twinning has been observed. Angastonite is triclinic, P1̄, with a = 13.303(1) Å, b = 27.020(2) Å, c = 6.1070(7) Å α = 89.64(1)°, β = 83.44(1)°, γ = 80.444(8)°, V = 2150.5(4) Å3, with Z = 6. The mineral is optically biaxial (+), with refractive indices of α = 1.566(2), β = 1.572(2) and γ 1.584(2) and with 2Vmeas = 70(2)° and 2Vcalc = 71°. Orientation: X ≈ a, Y ≈ b, Z ≈ c; with crystals showing parallel extinction and no axial dispersion. Dmeas is 2.47 g/cm3, whilst Dcalc is 2.332 g/cm3. The strongest four powder-diffraction lines [d in Å, (I/I°), hkl] are: 13.38, (100), 020; 11.05, (25), 11̄0; 5.73, (23), 101, 230 and 111; 8.01, (21), 130. Angastonite is likely to be related to the montgomeryite-group members and have a similar crystal structure, based on slabs of phosphate tetrahedra and Al octahedra.

A blue-green scaly coating on a slaty specimen from the Bastenberg mine, near Ramsbeck, Germany, yielded an X-ray powder pattern akin to schulenbergite. Chemically it is the zinc analogue of schulenbergite. Electron-probe data, XRF and ICP/OES analyses are presented which demonstrate two distinct zinc-rich compositions. Thermogravimetric analysis, together with CHN results, suggest the phase may contain 3-4 water molecules. Powder data are indexed on a hexagonal cell with a 8.293(2) Å, c 7.247(4) Å and cell volume 431.6(2) Å3, with Z = 1.

The hydrocerussite-related phase, NaPb5(CO3)4(OH)3, has been found as colourless lamellar crystals in cavities within a pebble of the ancient marine slag collected in the Pacha Limani area of the Lavrion mining district, Attiki, Greece. This phase of anthropogenic origin was characterized by electron microprobe, infrared spectroscopy, powder and single-crystal X-ray diffraction. The unique crystal structure (P63/mmc, a = 5.2533(11), c = 29.425(6) Å, V = 703.3(3) Å3 and R1 = 0.047) is based upon structurally and chemically different electroneutral blocks. Each of the blocks can be split into separate sheets. The outer sheets in each block are topologically identical and have the composition [PbCO3]0. The [Pb(OH)2]0 lead hydroxide sheet is sandwiched between the two [PbCO3]0 sheets resulting in the formation of the first block [Pb3(OH)2(CO3)2]0 structurally and compositionally identical to that one in hydrocerussite Pb3(OH)2(CO3)2. Similarly the [Na(OH)]0 sheet is sandwiched between another two [PbCO3]0 sheets thus forming the [NaPb2(OH)(CO3)2]0 block described previously in the structure of abellaite NaPb2(OH)(CO3)2. Stereochemically active lone electron pairs on Pb2+ cations are located between the blocks. There are two blocks of each type per unit cell, which corresponds to the following formula: [Pb3(OH)2(CO3)2][NaPb2(OH)(CO3)2] or NaPb5(CO3)4(OH)3 in the simplified representation. The formation of NaPb5(CO3)4(OH)3 in Lavrion slags is by the contact of lead-rich slags with the sea water over the last two thousand years.

The crystal chemistry of a meso-octahedral Li,Be-bearing mica from the Harding pegmatite (Dixon, Taos County, New Mexico, USA) has been investigated by constant-wavelength single-crystal neutron diffraction at 20 K, single-crystal X-ray diffraction at 100 K and inductively coupled plasma-atomic emission spectrometry (ICP-AES). The chemical composition based on ICP-AES analysis leads to the following chemical formula (calculated on the basis of 12 oxygen atoms): Ca(Na0.26K0.04Ca0.69)∑0.99M(Li0.29Mg0.03Fe0.023+Al1.78)∑2.12T(Al1.73Be0.16Si2.11)S4.00O12H2.53. The apparent excess of H is probably due to the fact that the fraction of H2O was assumed by difference to 100 wt.%, and slightly overestimated. On the basis of the previous experimental findings on Li,Be-bearing mica, X-ray (at 100 K) and neutron (at 20 K) structure refinements were performed in the space groups Cc and C2/c. The neutron structure refinement in the space group Cc offers a view about the (Al,Be,Si)-tetrahedral ordering: the best fit of the refinement was reached with the T1 and T4 sites occupied by (Be + Al) and T2 and T3 fully occupied by Si. This leads to a final population of T(Al1.88Be0.12Si2.00)∑4.00 p.f.u., in reasonable agreement with the chemical analysis. The neutron refinement provides unambigous evidence of the occurrence of Li at the M1 site. The refined fraction of Li at the M1 site ranges between 0.27 and 0.29 a.p.f.u., in excellent agreement with the chemical analysis. The presence of Li, at least at a significant level, at the M2 (and M3) site can be ruled out, as a full site occupancy with the scattering length of Al was obtained. The location of the H sites and the complex hydrogen-bonding scheme are described. A comparison between the structure features of this Li,Be-mica and other brittle micas is carried out.