The paper opens a series devoted to the mineral diversity of the Mochalin Log rare earth element (REE) deposit, South Urals, Russia. There is a brief outline of the history of studies and geology of the deposit as well as the description of two new isostructural gatelite-group minerals, ferriperbøeite-(La) (CaLa3)(Fe3+Al2Fe2+)[Si2O7][SiO4]3O(OH)2 and perbøeite-(La) (CaLa3)(Al3Fe2+)[Si2O7][SiO4]3O(OH)2. Both minerals occur in polymineralic nodules and are associated with one another and allanite-(Ce), allanite-(La), bastnäsite-(Ce), bastnäsite-(La), ferriallanite-(Ce), ferriallanite-(La), ferriperbøeite-(Ce), perbøeite-(Ce), törnebohmite-(Ce) and törnebohmite-(La). The new minerals form isolated anhedral grains up to 0.3 mm [ferriperbøeite-(La)] and 0.5 mm [perbøeite-(La)] across and granular aggregates up to 1.5 mm × 0.5 mm [ferriperbøeite-(La)] and 3 mm × 1 mm [perbøeite-(La)]. Both minerals are brownish-black with vitreous lustre. Dcalc = 4.510 [ferriperbøeite-(La)] and 4.483 [perbøeite-(La)] g cm–3. They are optically biaxial (+); ferriperbøeite-(La): α = 1.788(5), β = 1.790(5), γ = 1.810(5) and 2Vmeas = 40(10)°; perbøeite-(La): α = 1.778(8), β = 1.783(8), γ = 1.805(8) and 2Vmeas = 40(10)°. Chemical data [wt.%, electron-microprobe; Fe3+:Fe2+ ratio from charge-balance requirements, H2O by stoichiometry; ferriperbøeite-(La)/perbøeite-(La)] are: CaO 4.91/4.81, ThO2 0.00/0.32, La2O3 23.75/22.16, Ce2O3 19.69/20.05, Pr2O3 0.85/1.09, Nd2O3 1.48/2.18, MgO 1.47/1.38, Al2O3 10.68/11.25, MnO 1.07/0.92, FeO 3.04/3.35, Fe2O3 5.31/3.78, TiO2 0.19/0.19, SiO2 27.47/27.35, F 0.11/0.23, H2O 1.61/1.54, –O = F –0.05/–0.10, total 101.58/100.50. The empirical formulae based on O20(OH,F)2 are for ferriperbøeite-(La): (Ca0.95La1.58Ce1.30Nd0.10Pr0.06)Σ3.99(Al2.27Fe3+0.72Fe2+0.46Mg0.40Mn0.16Ti0.03)Σ4.04Si4.96O20[(OH)1.94F0.06]; and for perbøeite-(La): (Ca0.94Th0.01La1.49Ce1.34Nd0.14Pr0.07)Σ3.99(Al2.42Fe3+0.52Fe2+0.51Mg0.38Mn0.14 Ti0.03)Σ4.00Si4.99O20[(OH)1.87F0.13]. Both minerals are monoclinic, P21/m; the unit-cell parameters [ferriperbøeite-(La)/perbøeite-(La)] are: a = 8.9458(2)/8.9652(4), b = 5.72971(13)/5.7306(2), c = 17.6192(3)/17.6770(9) Å, β = 115.9497(19)/116.053(6)°, V = 812.06(3)/815.88(6) Å3 and Z = 2/2. The crystal structures are solved on a single crystal and converged to R = 0.0355 [ferriperbøeite-(La)] and 0.0750 [perbøeite-(La)]. Ferriperbøeite-(La) and perbøeite-(La) are named as the La-analogues of ferriperbøeite-(Ce) and perbøeite-(Ce), respectively.

Gallium (Ga) and germanium (Ge) are technologically important critical elements. Lead blast furnace slags from Tsumeb, Namibia, comprise over two million metric tons of material that contains high levels of Ga (135–156 ppm) and Ge (128–441 ppm) in addition to significant Zn concentrations (up to 11 wt.%) and represent a potential resource for these elements. A combination of mineralogical and chemical methods (PXRD, FEG-SEM-EPMA and LA-ICP-MS) indicated different partitioning of Ga and Ge within the individual slag phases. Gallium is predominantly bound in small euhedral crystals of Zn–Fe–Al spinels (<10 μm in size), exhibiting concentrations in the range of 480–1370 ppm (up to 0.004 atoms per formula unit, apfu). Concentrations of Ga in other phases (e.g. melilite) are systematically below 90 ppm. The principal host of Ge is the silicate glass and, to a lesser extent, silicates (melilite and olivine group phases). Concentrations of Ge in glass attained a concentration of 470 ppm (EPMA), but the LA-ICP-MS analysis of glass matrix containing submicrometre spinel crystallites indicated that average Ge levels vary in the range of 113–394 ppm. In the potential extraction of Ga and Ge, the results indicate that ultrafine milling is needed to liberate the Ga- and Ge-hosting phases prior to metallurgical processing of the slag.

Hillebrandite was first characterized by Wright as a white, fibrous mineral with the composition 2CaO.SiO2.H2O, optical properties αNa 1·605±0.005, γNa 1·612±0.003, moderately weak birefringence, parallel extinction, optic axial angle 2E between 60 and 80° and density 2.692. X-ray powder data were first published by Vigfusson, but these have not been substantiated by later investigators (Clark and Bunn, McMurdie and Flint, and Heller and Taylor). Synthetic dicalcium silicate β-hydrate has been found to resemble hillebrandite closely.

The mineral, for which the name isokite is now proposed, occurs in the carbonatite plug which forms Nkumbwa Hill Oat. 10° 10' S. long. 32° 51' E.), 15 miles east of Isoka (pronounced Iso̅ka) in Northern Rhodesia. A preliminary account of this interesting mineral locality has already been published (Reeve and Deans, 1954) and a more detailed account is now in preparation, so that only the main features of the occurrence need be mentioned here. The carbonatite plug or pipe, 0.6 by 1 mile across and rising to a height of 1000 feet above the surrounding country, pierces granitic and micaceous gneisses which are fenitized to a distance of 500 yards from the walls of the pipe, but, unlike the classic carbonatite complexes, no intrusive alkalic rocks are exposed.

Baron Karl Ludwig von Reichenbaeh (1788-1869) was born at Stuttgart, ennobled in 1839 by the King of Wiirttemberg, and died at Leipzig. But he spent most of his life in Austria, where he had iron works and estates in Moravia and Galicia and a castle near Vienna. Earning a livelihood as a copyist in the state archives, he was able to obtain a university education, and he started his career as a works chemist. He produced many papers on the distillation products of coal, tar, oil, &c, and was the discoverer of creosote and solid paraffin. He gained considerable notoriety with his ideas and books on what he called 'od' or 'odylic force', a combination of animal magnetism, light, heat, force of crystallization, &c., capable of producing hypnotism. The fall in 1833 of a shower of meteorites, which he witnessed near his works at Blansko in Moravia, fired his intense enthusiasm for the subject of meteorites, on which he wrote 29 scientific papers (1835—65) and many newspaper articles.

Wollastonite at Scawt Hill, Co. Antrim, ocours as a constituent of both the exogeneous and endogeneous contactzones of the dolerite. In the former it is associated only with flint nodules in the metamorphosed chalk, in the latter, however, commonly as a minor constituent of certain of the hybrid types.

In my original account a wollastonite-bearing augite-dolerite from this latter zone was figured without further description in the text (plate xvII, fig. 3). In examining the optical characters of wollastonites associated with hedenbergite, I had occasion to turn again to the wollastonites of this particular rock type.

As indicated in the explanation of the figured section (loc. cir., p. 467), the dolerite is built essentially of sharply zoned brown titanaugite, labradorite, wollastonite, iron-ores, interstitial thomsonite, analcime, and accessory sphene. In this aggregate wollastonite forms subidiomorphic crystals averaging 1 ram. in size, and from a series of sections its predominant forms can be readily made out.

In the Carboniferous-Permian dyke-suite north of Loch Sunart, Argyll, a complete gradation is displayed from olivine-dolerite to camptonite. The dolerites are more numerous than the camptonites, and dykes of monchiquite are rare. A small number of minettes and allied lamprophyre types of Devonian age are also present. New analyses of biotite and diopside from a minette and of augite and hornblende from a camptonite are presented, with optical data, and the classification of the dykes briefly discussed.

These two minerals are analogous silver compounds with similar pseudo-hexagonal monoclinic form and similar compositions: polybasite, 8(Ag,Cu)2.(Sb,As)2S3, and pearceite, 8(Ag,Cu)2S.As2S3. Cu replaces Ag in considerable and varying amounts in both minerals, and in polybasite there may also be substantial replacement of Sb by As. However, the rather numerous existing analyses do not indicate continuous chemical variation from arsenian polybasite to pearceite, and therefore it is proper to recognize the two minerals as distinct species rather than end-members of a series.

In the investigation of the system CaO–MgO–SiO2 by Ferguson and Merwin the orthositicate 3CaO.MgO.2SiO2 was not observed, and the existence of this compound was first proved in 1921 by Larsen and Foshag who detected it in a contact-altered limestone at Crestmore, California, and gave to it the name merwinite. Since then this compound has been found in contact-altered limestones at Scawt Hill, Antrim, near Neihart in the Little Belt Mts. of Montana, and at Velardeña, Mexico. The history of the recognition of merwinite as an artificial mineral is less easy to trace, but it seems that research workers on refractory bricks were the first to recognize its existence. Thus U.S.A. Patents applied for in the years 1934 and 1935 and British Patents applied for on 11.10.1935 and 19.5.1936 by Non-Metallic Minerals Inc. specify merwinite and periclase as the essential constituents of a refractory brick produced by firing mixtures of dolomite and serpentine, dolomite and sand, or impure magnesite and dolomite at temperatures varying between 2700° and 2900° F.

Marécottite, ideally Mg3[(UO2)4O3(OH)(SO4)2]2(H2O)28, a triclinic, Mg-dominant member of the zippeite group, was described originally from a small uranium deposit at La Creusaz in Wallis (Switzerland). It has recently been found at Jáchymov (Czech Republic), where it forms exceptional crystals, up to 0.3 mm across. According to an electron microprobe study of these crystals, marécottite from Jáchymov is chemically similar to the material from the La Creusaz deposit. However, the Jáchymov crystals exhibit more cation substitution (Zn2+ and Mn2+ for Mg2+). The chemical composition of marécottite from Jáchymov corresponds to the empirical formula [(Na0.05K0.07)Σ0.12(Mg1.83Zn0.41Mn0.41Cu0.15Ni0.08)Σ2.88Al0.07]Σ3.07(UO2)8[(SO4)3.77(SiO4)0.21]Σ3.98O6(OH)1.84·28H2O (the mean of four representative spots; calculated on the basis of eight U atoms and 28 H2O per formula unit and 1.84 OH for charge balance). According to single-crystal X-ray diffraction, marécottite from Jáchymov is triclinic, P1, a = 10.8084(2), b = 11.2519(3), c = 13.8465(3) Å, α = 66.222(2), β = 72.424(2), γ = 70.014(2)o, V = 1421.57(6) Å3 and Z = 1. The crystal structure was refined from a highly redundant dataset (30,491 collected reflections) to R1 = 0.0367 for all 7042 unique reflections. The refined structure confirms the previously determined structure for the crystal from the La Creusaz deposit. An extensive network of hydrogen bonds is an important feature that keeps the whole structure together, but the positions of H atoms had not been determined previously. The H-bond scheme proposed based on a detailed bond-valence analysis and the role of different types of molecular H2O in the structure is discussed.

Fogoite-(Y), Na3Ca2Y2Ti(Si2O7)2OF3, is a new mineral from the Lagoa do Fogo, São Miguel Island, the Azores. It occurs in cavities as highly elongated (on [001]) prisms, up to 2000 μm long and 50 μm× 50 μm in cross-section, associated with sanidine, astrophyllite, fluornatropyrochlore, ferrokentbrooksite, quartz and ferro-katophorite. Crystals are generally transparent and colourless, with vitreous lustre, occasionally creamy white. Fogoite-(Y) has a white streak, splintery fracture and very good {100} cleavage. Mohs hardness is ∼5. Dcalc. = 3.523 g/cm3. It is biaxial (+) with refractive indices (λ = 590 nm) α = 1.686(2), β = 1.690(2), γ = 1.702(5); 2Vmeas. = 57(1)° and 2Vcalc. = 60°. It is nonpleochroic. Fogoite-(Y) is triclinic, space group P1, a = 9.575(6), b = 5.685(4), c = 7.279(5) Å, α = 89.985(6), β = 100.933(4), γ = 101.300(5)°, V = 381.2 (7) Å3. The six strongest reflections in the powder X-ray diffraction data [d (Å), I, (hkl)] are: 2.954, 100, (1̄1̄2, 3̄10); 3.069, 42, (300, 01̄2); 2.486, 24, (310, 21̄2); 3.960, 23, (1̄1̄1, 2̄10); 2.626, 21, (2̄20); 1.820, 20, (1̄04). Electron microprobe analysis gave the following empirical formula calculated on 18 (O + F) (Na2.74Mn0.15)∑2.89Ca2[Y1.21(La0.01Ce0.03Nd0.03Sm0.02Gd0.08Dy0.08Er0.05Yb0.04Lu0.01)∑0.35Mn0.16Zr0.11Na0.09Fe0.072+Ca0.01]∑2(Ti0.76Nb0.23Ta0.01)∑1(Si4.03O14)O1.12F2.88, Z = 1. The crystal structure was refined on a twinnedcrystal to R1 = 2.81% on the basis of 2157 unique reflections (Fo > 4σFo) and is a framework of TS (Titanium Silicate) blocks, which consist of HOH sheets (H – heteropolyhedral, O – octahedral) parallel to (100). In the O sheet, the the [6]MO(1) site is occupied mainly by Ti, <MO(1)–ϕ> = 1.980 Å, and the [6]MO(2) and [6]MO(3) sites are occupied by Na and Na plus minor Mn, <MO(2)–ϕ>= 2.490 Å and <MO(3)–ϕ> = 2.378 Å. In the H sheet, the two [4]Si sites are occupied by Si, with <Si–O> = 1.623 Å; the [6]MH site is occupied by Y and rare-earth elements (Y > REE), with minor Mn, Zr, Na, Fe2+ and Ca, <MH–ϕ> = 2.271 Å and the [6]AP site is occupied by Ca, <AP–ϕ> = 2.416 Å. The MH and AP octahedra and Si2O7 groups constitute the H sheet. The ideal compositions of the O and two H sheets are Na3Ti(OF)F2 and Y2Ca2(Si2O7)2 apfu. Fogoite-(Y) is isostructural with götzenite and hainite. The mineral is named after the type locality, the Fogo volcano in the Azores.

Coccolithophores, among which Emiliania huxleyi is the most abundant and widespread species, are considered the most productive calcifying organism on earth. The export of organic carbon and calcification are the main drivers of the biological CO2 pump and are expected to change with oceanic acidification. Coccolithophores are further known to produce transparent exopolymer particles (TEP) that promote particle aggregation. As a result, the TEP and biogenic calcium carbonate (CaCO3) contribute to the export of carbon from the surface ocean to deep waters. In this context, we followed the development and the decline of E. huxleyi using batch experiments with monospecific cultures. We studied the link between different processes such as photosynthesis, calcification and the production of TEP. The onset of calcification was delayed in relation to photosynthesis. The timing and the general feature of the dynamics of calcification were closely related to the saturation state of seawater with respect to calcite, Ωcal. The production of TEP was enhanced after the decline of phytoplankton growth. After nutrient exhaustion, particulate organic carbon (POC) concentration increased linearly with increasing TEP concentration, suggesting that TEP contributes to the POC increase. The production of CaCO3 is also strongly correlated with that of TEP, suggesting that calcification may be considered as a source of TEP precursors.

The oxidation state of Fe and precipitates within olivine phenocrysts from an olivine-basalt from Kuroshima volcano, Goto Islands, Nagasaki Prefecture, Japan, were determined using electron microprobe analysis, 57Fe Mössbauer spectroscopy, Raman spectroscopy and transmission electron microscopy, to examine the formation process of the Fe-bearing precipitates.

The average Fo content of the olivine phenocrysts is 76.2 mol.%. The olivine phenocrysts occasionally have precipitate minerals at their rims, especially on rims near vesicles. The 57Fe Mössbauer spectrum of olivine separates consists of two doublets assigned to Fe2+ at the octahedral M1 and M2 sites, and a Fe3+ doublet at the M1 and M2 sites. The Fe2+:Fe3+ ratio is 90(5):10(1). The precipitates at the rims of the olivine phenocrysts consistof magnetite and enstatite showing coaxial relations with host olivine, and grow parallel to the olivine c axis. Moreover, clusters consisting of nanoscale domains of a few tens of nm in size occur in the host olivine. Their rounded form and appearance in transmission electron microscope images are similar to those of the magnetite precipitates, but they have an olivine structure and can be regarded as embryos of magnetite within the olivine.

The oxidation process of olivine phenocrysts under cooling conditions is: (1) formation of magnetite embryos on the rims of olivinephenocrysts; (2) formation of enstatite-like pyroxene domains by depletion of Fe in olivine due to the generation of magnetite embryos; (3) crystallization of magnetite and enstatite-like pyroxene precipitates.

Levantite, with the end-member formula KCa3(Al2Si3)O11(PO4), is the phosphate analogue of latiumite, KCa3(Al3Si2)O11(SO4, CO3) found in gehlenite–wollastonite hornfels on Har Parsa, Negev Desert, Israel. Levantite forms later zones on long-prismatic crystals of latiumite. Rarer homogeneous colourless levantite crystals up to 0.2 mm long and with mean composition (K0.94Ba0.01Na0.01□0.04)Σ1.00(Ca2.96Mg0.03)Σ2.99{(Si2.69Al2.06Fe3+0.16P0.06)Σ4.97O11}[(PO4)0.65(SO4)0.35]Σ1.00 were noted. Minerals of the levantite–latiumite series are associated with gehlenite, wollastonite, clinopyroxene of the esseneite–diopside series, anorthite and Ti-bearing andradite. Levantite crystalises in space group P21 with unit-cell parameters a = 12.1006(9) Å, b = 5.1103(4) Å, c = 10.8252(9) Å, β = 107.237(8)°, V = 639.34(9) Å3 and Z = 2. The structure of levantite is analogous to latiumite. It is formed by tetrahedral hybrid zweier double layers [(Si,Al)10O22] connected by Ca atoms. Three Ca atoms linked to different double layers are bridged over by (PO4) and minor (SO4) groups. K atoms reside in the cavities between two superimposed zweier double layers. The measured micro-indentation hardness of levantite gave VHN50 = 580(19) (mean of 14), range 550–611 kg/mm2, which correlates with 5 on the Mohs scale. Cleavage is good on (100). Twinning on (100) is polysynthetic or simple. The calculated density is 2.957 g cm–3. Levantite is optically negative with α = 1.608(2), β = 1.618(2), γ = 1.622(2) (λ = 589 nm), 2Vmeas. = 70(5)° and 2Vcalc. = 64.3°. Dispersion of the optical axes r > v is weak; the optical orientation is: Z = b, X ^ c = 22–27°; and it is non-pleochroic. Minerals of the levantite–latiumite series from Israel show characteristic Raman spectra with the main bands at 994 cm–1 [ν1(SO4)2–] and 945 cm–1 [ν1(PO4)3–]. The band intensity ν1(PO4)3–/ν1(SO4) ratio is well correlated with P and S contents in the investigated minerals. The strongest lines in the powder diffraction pattern [dobs, Å (I, %) (hkl)] are: 3.0762(100)(310), 2.8551(96)($\bar 2$13), 2.9704(92)($\bar 3$12), 2.8573(83)(013), 2.5552(66)(020), 2.8228(48)(212), 2.8893(40)(400), and 3.0634(30)(103).

A number of representative examples of the Lewisian acid pegmatites of South Harris are described, and the presence of the following minerals has been established: quartz, albite, microcline, biotite, muscovite, magnetite, beryl, spessartine, gahnite, eolumbite, monazite, zircon, pyrite, epidote, tourmaline, apatite, thorite, uraninite, thorogummite, uranophane, kasolite, betafite (?), and allanite. Spectrographic, optical, and X-ray powder data are given for some of these minerals, together with chemical analyses of magnetite, biotite, columbite, gahnite, and spessartine. It is believed that gahnite, nranophane, and the pyrochlore mineral (probably betafite) are recorded for the first time from Britain.

Single crystals of synthetic reidite and natural radiation-damaged zircon from Okueyama, Japan were investigated using X-ray diffraction. The pressure-induced zircon–reidite transition is described by the twisting and translations of SiO4 tetrahedra with disappearance of the SiO4–ZrO8 shared edges. The lattice of radiation-damaged zircons expands mainly from α-decays of radioactive elements such as U and Th. Although old radiation-damaged zircons show anomolous lattice distortion, young radiation-damaged zircons do not show such distortions. These distortions are caused by thermal recovery that suppresses the Si4+–Zr4+ repulsion between the SiO4 tetrahedron and ZrO8 dodecahedron. These changes in structure can be understood by considering the cation–cation repulsion between the SiO4–ZrO8 shared edges.