In this paper are embodied the results of an examination of the specimens of lead slags from Laurium in the British Museum. On some of the specimens a new mineral, paralaurionite, was found, which possesses the same chemical composition as laurionite, but entirely different morphological and optical characters.

In addition to crystals of the four minerals given in the title, a few crystals oi matloekite and anglesite were noticed, and on one specimen there is a radiating group of prismatic crystals of penfieldite.

Thermal behaviour of fibrous tremolite from Maryland, USA has been investigated in situ up to breakdown temperature. Tremolite can be found both as primary constituent and as contaminant in Asbestos Containing Materials (ACMs). The products of breakdown are subcalcic diopside and calcium-rich clinoenstatite in a 2:1 ratio, traces of hematite plus minor silica-rich amorphous material. Thermal expansion follows a regular trend up to 723 K before the onset of Fe2+ oxidation/OH– deprotonation which is completed at 1023 K. At 923 K the Fe3+ migration starts towards M(1) and the corresponding counter-migration of Mg to M(2) and M(3). At T close to structure breakdown, M(2) shows a significant site-scattering reduction possibly consistent with the occurrence of minor vacancies. In fully oxidised tremolite, Fe3+ is allocated prevalently at M(1) and subordinately at M(3). As it is well-known that M(1), along with M(2), is the most exposed octahedral site at the surface of amphiboles, most of the Fe3+ is available for participating in the Fenton-like reactivity of oxidised tremolite, potentially making it dangerous for human health. This point should be properly taken into account in the evaluation of the safety of thermally decomposed tremolite-containing ACMs, in particular in the case of accidentally incomplete treatments.

A common attribute of two rare natural chromium-bearing oxides: mcconnellite, CuCrO2, discovered more than 40 years ago in Guyana, and a new mineral ellinaite, CaCr2O4, described from two localities (Brazil and Israel) recently, is that these minerals are poorly studied due to their rarity and small size. Mcconnellite and ellinaite in the present study were found in varicoloured marbles of the pyrometamorphic Hatrurim Complex in the Tulul Al Hammam area, Daba-Siwaqa, Jordan. Structural data obtained for ellinaite (Pnma, a = 9.0875(2), b = 2.9698(1), c = 10.6270(3) Å and V = 286.80(2) Å3), with an empirical formula (Сa1.00Sr0.01)Σ1.01(Cr3+1.79Al0.07Ca0.04Fe3+0.04 Ti4+0.03Mg0.03)Σ2.00O4, is similar to the structural data of synthetic analogue β-CaCr2O4 but differs significantly from the data obtained for ellinaite from Brazil and Israel despite the fact that all the natural phases have a similar composition. Single-crystal X-ray diffraction data for mcconnellite from Jordan (R$\bar{3}$m, a = b = 2.9756(1) and c = 17.124(1) Å) with composition (Cu0.98Ca0.03Sr0.01)Σ1.02(Cr3+0.90Al0.05 Fe3+0.03)Σ0.98O2, is the first determination of a natural Cu-delafossite-type structure. This paper also presents the results of a single-crystal Raman study for mcconnellite and ellinaite, which indicates that the spectral features of these minerals is dependent on crystal orientation.

Thermodynamic data are constrained by the interrelated thermodynamic equations in addition to the observational measurements and their uncertainties. The consequence is a network of thermodynamic properties that can be evaluated for their internal consistency. In this study, three fluoride minerals that can cause high fluoride concentrations in groundwaters are evaluated for their solubilities and their internal thermodynamic consistency with calorimetric, isopiestic and electrochemical measurements: fluorite, CaF2, cryolite, Na3AlF6, and villiaumite, NaF. This evaluation involves the three solids and 13 aqueous species, the free ions of Ca2+, Na+, Al3+ and F–, and the hydroxido and fluorido complexes of Al3+, and the CaF+ ion pair. For the fluorite–cryolite–villiaumite–aqueous species network, the number of components is minimal, and the solubility studies are mostly of high quality. Re-evaluations of original data using PHREEQC helps to broaden the quantitative evaluation of thermodynamic properties and to resolve apparent discrepancies. A check on this thermodynamic network shows that through a careful appraisal of the literature, a highly consistent set of values can be derived. The resultant infinite-dilution solubility-product constants at 25°C and 1 bar are: for fluorite solubility, logKsp = –10.57 ± 0.08; for cryolite solubility, logKsp = –33.9 ± 0.2; and for villiaumite solubility, logKsp = –0.4981 ± 0.003.

One of the most important isotopes to be considered for disposal in the proposed UK Geological Disposal Facility (GDF) for higher-activity radioactive wastes will be 99Tc, due to its long half-life, high fission yield and ability to migrate through the geosphere as the pertechnetate ion. Much of the Tc is likely to be in the lower Tc(IV) oxidation state due to the low Eh in the near field. Batch Tc(IV) sorption experiments have been performed from pH 3–13, using 95mTc as a spike, in the presence of quartz, hematite, goethite, plagioclase feldspar, sand and shale. Solutions containing Tc(IV) were prepared at trace concentrations to avoid precipitation of TcO2. Values for the partition coefficient (Rd) were found to range from ∽4 up to ∽2 × 104 cm3 g–1. Rd was heavily dependent on pH in all cases, with the highest values being found in the circumneutral area. These data will inform the performance assessment for the near-field behaviour of technetium in the UK's planned higher-activity wastes GDF. Surface complexation modelling has been performed, fitting the data using both monodentate and bidentate binding models.

Ilmenite–pyrophanite crystals from a garnet pegmatite dyke from the Upper Codera Valley (Sondrio, Italian Alps) showing exsolutions of titanohematite and columbite-tantalite were investigated by scanning and transmission electron microscopy. The titanohematite precipitates share the same crystallographic orientation of the ilmenite-pyrophanite host, are bean-shaped when observed on sections inclined to the pinacoidal section, and are elongated when observed on sections closer to the prism section, possibly because of their discoidal shape parallel to (001). The columbite-tantalite precipitates form a hexagonal network of needles elongated along ⟨110⟩ of the ilmenite–pyrophanite and titanohematite host. The following crystallographic relationship was established: [100]Col//[001]Ilm; [001]Col//[110]Ilm; , which can be explained in terms of preservation of the oxygen close packing between the ilmenite and columbite structures. The interfaces between any two of the three different phases are coherent but show lattice strain contrast and sometimes dislocations because of their different unit-cell dimensions. On the basis of textural observations, titanohematite is supposed to exsolve first, followed by columbite-tantalite at temperatures below 500°C. The addition of MnO to the Fe2O3–FeTiO3 system is supposed to considerably influence the topology of the related T-X phase diagram and the solubility of Nb2O5 and Ta2O5 in this system.

Trioctahedral ferromagnesium micas from the Archaean amphibolites of the Kola super-deep borehole (KSDB-3) complex have been compared with those from analogous Archaean surface rocks in an integrated study of their chemical compositions and structural states (using wet chemistry, microprobe, X-ray, Mössbauer and infrared methods). Reports on both the experimental procedure and the crystal chemistry of the trioctahedral micas are given. This has enabled the revision of the assignment of individual infrared (IR) absorption bands for the hydroxyl ion (vOH−), and demonstrated the possibility of determining the content of Mg, Fe2+, R3+; cations and vacancies in the octahedral sheet to within a few hundredths of atomic units on the basis of the infrared and Mössbauer data. Proof was found of the presence of molecular water replacing K+ in the interlayer, which results in anomalous variations in the cell parameters, as the mica structure expands in response to the ingress of H2O. Variations in the degree of non-stoichiometry of the micas is related to the presence of structural H2O and of octahedral M1 vacancies. We found that samples recovered from depth within the borehole display lower degrees of octahedral order than those found in the analogous surface rocks.

The structure of the high-temperature form of CaSeO4, formed by dehydration of the gyspum-type structure dihydrate is presented. The material is equivalent to that described previously as a P212121 form, but is however, a monazite with unit cell a = 6.85661(16) Å, b = 7.04962(15) Å, c = 6.68817(15) Å and β = 104.2675(21)° in space group P121/n1. Also presented is evidence for two intermediate trigonal and pseudo-trigonal phases related to the structurally similar minerals rhabdophane, bassanite, and γ-CaSO4. This result permits closer comparisons between intermediate-temperature structures of the selenate with related sulphates, and orthophosphates with a view to extending structural stability via synthesis of solid-solutions.

Borehole samples from the Wildmoor Sandstone Formation have been analysed for whole-rock major and trace elements and the mineralogy determined by X-ray diffraction and conventional thin sections. The forty-two samples studied were obtained from boreholes drilled in a long established effluent site and from control boreholes away from the site. Elements are associated with one or more of calcite, quartz, K-feldspar, and clay plus oxide. The most important mineralogical change due to current infiltration is progressive loss of calcite. Background element concentrations are established and only Pb, and in one sample Cu and Zn, are found in higher concentrations representing anthropogenic additions to the system.

A uranopilite from The South Alligator River, Northern Territory, Australia, has been studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) with EDAX attachment, and thermogravimetry in conjunction with evolved gas mass spectrometry. The XRD shows that the mineral is a pure uranopilite with few if any impurities. The SEM images show that the uranopilite consists of elongated crystals, up to 50μm long and 5 μm wide. Thermogravimetry combined with mass spectrometry shows that dehydration occurs at ∼31°C resulting in the formation of metauranopilite. The first dehydration step over 20–71°C corresponds to a decrease of 5.4 wt.%, equivalent to 6.076 H2O. The second dehydration step, over the temperature range 71 –162.4°C corresponds to a decrease of 4.7 wt.%, equivalent to 5.288 H2O, making a total of 11.364 moles of H2O, close to 12 H2O for uranopilite.

Dehydroxylation takes place over the temperature range 80–160°C. The loss of sulphate occurs at higher temperatures in two steps at 622 and 636°C. A mass loss also occurs at 755°C, accounted for by evolved oxygen.

Manganese incorporation in synthetic hercynite, and partitioning between hercynite and silicate melt synthesized at 1.0 GPa, 1250°C, and at an fO2 buffered by Fe–FeO, has been studied by X-ray absorption spectroscopy and single-crystal X-ray structure refinement. Spectra indicate the presence of both Mn2+ and Mn3+ (and possibly also Mn4+) in synthetic hercynite and partitioning of Mn2+ into the melt phase, and Mn3+ into hercynite, respectively, under run conditions. X-ray refinement is consistent with partial disorder of Fe and Al across tetrahedral and octahedral sites. A higher than expected degree of Fe-Al disorder in the Mn-bearing hercynite can be explained by preferential incorporation of Mn2+ onto the tetrahedral site, and indicates that Fe-Al disorder in pure, stoichiometric hercynite cannot necessarily be used to determine closure temperatures in natural spinel. However, partitioning of Mn2+ and Mn3+ between melt and hercynite suggests that Mn incorporation in hercynite could be used as a measure of fO2 conditions in magmas during spinel crystallization.

A study of apatite crystals from the Asio mine, Japan, showed sectoral texture related to the growth of the crystal, and with optically biaxial properties within the sectors. Wet chemical analysis gave a composition Ca5(PO4)3(F0.64,OH0.38,Cl0.01)1.03 for the specimen.

Additional diffraction spots were not observed in precession and oscillation X-ray photographs and electron diffraction photographs. Since the internal textures correlate with the surface growth features, it is suggested that the internal textures and the unusual optical properties were produced during nonequilibrium crystal growth. The fluorine/hydroxyl sites in hexagonal apatite are symmetrically equivalent in the solid crystal but, at a growth surface, this equivalence may be lost, resulting in a reduction of crystal symmetry. Heating of the apatite to about 850°C results in the almost complete disappearance of the optical anomalies due to disordering, which may be related to the loss of hydroxyl from the crystal.

The crystal structure of a Mn-bearing kilchoanite, Ca2.33Mn0.67Si2O7, orthorhombic, I2cm, a = 11.356(2), b = 5.007(1), c = 21.817(1)Å, Z = 8, was refined using single-crystal X-ray data to an R value of 3.1% for 1725 unique reflections. It is isostructural with kilchoanite, Ca3Si2O7, and shows a partial disorder of Mn and Ca over the four octahedral sites. On a basis of occupancy refinement, the M3 site (〈M3-O〉 = 2.307 Å) contains 0.508Ca and 0.492Mn, and the M4 site (〈M4-O〉 = 2.346 Å) contains 0.822Ca and 0.178Mn, whereas the M1 and M2 sites (〈M1-O〉 = 2.538 Å, (〈M2-O〉 = 2.380 Å) are occupied only by Ca. Substitution of Mn cations for Ca can be interpreted as taking place on the following sites in preferential order: (1) the smaller Ca site; (2) the less distorted Ca site; (3) the Ca site showing a loss in neutrality of formal electrostatic valence. A statistical survey of Si-O-Si angles observed in silicates containing [Si2O7] groups confirms that these angles become smaller with an increase in the coordination number of the bridging oxygen. Oversaturation of electrostatic bond-strength to the bridging oxygen in some groups of the crystal structures with two tetrahedra sharing a vertex (pyro-anion, ), which is caused by increase in the coordination number of the bridging oxygen and/or by T cations with larger charge than 4+, results in longer T-Obr bonds length and in smaller T-Obr-T angles.

Structural modifications with temperature of adamite, Zn2(AsO4)(OH), were determined by single-crystal X-ray diffraction up to dehydration and collapse of the crystal structure. In the temperature range 25–400°C, adamite shows positive and linear expansion. Axial thermal expansion coefficients, determined over this temperature range, are αa = 1.06(2) × 10–5 K–1, αb = 1.99(2) × 10–5 K–1, αc = 3.7(1) × 10–6 K–1 and αV = 3.43(3) × 10–5 K–1. Axial expansion is then strongly anisotropic with αa:αb:αc = 2.86: 5.38 : 1. Structure refinements of X-ray diffraction data collected at different temperatures allowed us to characterize the mechanisms by which the adamite structure accommodates variations in temperature. Expansion is limited mainly by edge sharing Zn(2) dimers along a and by edge sharing Zn(1) octahedra chains along c; on the other hand, connections of polyhedra along b, the direction of maximum expansion, is governed by corner sharing. Increasing temperature induces mainly an axial expansion of Zn(1) octahedron, which becomes more elongated, and no significant variations of the Zn(2) trigonal bipyramids and As tetrahedra. Starting from 400°C, deviation from a linear evolution of unit-cell parameters is observed, associated with some deterioration of the crystal, a sign of incipient dehydration. The process leads to the formation of Zn4(AsO4)2O.

Albertiniite, Fe2+(SO3)·3H2O, is a new Fe2+ sulfite trihydrate, related chemically to gravegliaite. It occurs at the Monte Falò Pb-Zn mine near Coiromonte, in the Armeno Municipality, Verbano–Cusio–Ossola Province, Italy. It is an intermediate product of oxidation between iron sulfides and sulfates, forming monoclinic, colourless to pale yellow, transparent crystals with a vitreous lustre. The mineral occurs associated with stolzite, pyromorphite, hinsdalite, plumbogummite, gibbsite, scheelite and jarosite on brittle fractures of quartz veins or chlorite-schist. Albertiniite is optically biaxial (+) with 2V(meas) ≈ 40° and 2V(calc) = 66°. The measured refractive indices, using sodium light (589 nm) are: α = 1.612(2)°, β = 1.618(2)° and γ = 1.632(2)°. The optical axis plane is parallel to the perfect {010} cleavage plane. It is non-fluorescent under shortwave (254 nm) or longwave (366 nm) ultraviolet light. The calculated density is 2.469 g cm–3 (from the crystal-structure refinement), or 2.458 g cm–3 (from the chemical analysis and the single-crystal unit-cell parameters). The empirical formula is (average of 16 spots and based on 3 anhydrous oxygen apfu) (Ca0.001Mg0.001Na0.003)∑1.061(S0.971O3)·2.84H2O, with the H2O content calculated by difference to 100 wt.%. Albertiniite is monoclinic, with space group P21/n. Its unit-cell parameters are: a = 6.633(1), b = 8.831(1), c = 8.773(1) Å, β = 96.106(8)° and V = 511.0(1) Å3, with Z = 4. The eight strongest measured lines in the powder X-ray diffraction pattern are [d in Å, (I/I0), (hkl)]: 4.072 (100) (1̄11), 3.539 (93) (1̄12), 5.533 (27) (1̄01), 6.167 (14) (011), 2.830 (14) (211), 4.998 (14) (101), 4.353 (12) (111) and 3.897 (12) (012). The mineral, which has been approved by the CNMNC, number IMA2015-004, is named albertiniite in honour of Claudio Albertini, an Italian mineral collector and expert in the systematic mineralogy of the Alps and pegmatites.

Two hundred years (1750–1950) of earthen architecture represents an important period of construction in the central region of Portugal. Earthen architecture is usually built close to the coast or to rivers and placed in sandy ground. The impact of rising damp is a general problem and efflorescences are a common cause of damage decay. This problem was studied in a building with two types of earthen construction, adobe masonry walls and formed masonry walls. The aim of this research was to characterise the conditions for the appearance and phase transitions of thénardite and mirabilite, and determine how to prevent progression of salt effects in the two types of wall to support future conservation measures. Laboratory capillarity and porosimetry tests with dolomitic air lime mortar and hygrothermal monitoring were pursued along with in situ tests. Visual assessment showed that the progression of salts depends on the composition of the earthen materials. To understand these differences, all crystalline solid phases were analysed by powder X-ray diffraction, and building interior hygrothermal conditions were monitored. An investigation into the influence of surface lime water painting and sacrificial mortar application on the crystallisation of sodium sulfates concluded that these also depend on the wall's composition. Data allowed us to conclude that inside the building the temperature and humidity [relative humidity (RH = 100 pw/p°w > 70)] conditions led to the adobe breakdown by the fast conversion from thénardite to mirabilite. Therefore, contact with wet atmospheres should be avoided and interior hygrothermal conditions should be controlled. Laboratory and in situ tests showed that the environmental conditions of the spaces had effects on the results. The results contribute to understanding of the salt progression and pattern of decay, as well as supporting future recommendations for building conservation, based on the identification of environmental conditions proper to their occurrence.