Mr. Arthur Russell collected in 1930 on Pim Hill, near the village of Harmer Hill, 6 miles north of Shrewsbury, Shropshire, specimens of Triassic sandstone encrusted with minute black crystals. They resemble very closely the material from Mottram St. Andrew, Cheshire, which was described and named mottramitc by Sir Henry E. Roscoe in 1876.1 Mr. Russell pointed out this resemblance and kindly placed his specimens of this rare British mineral at our disposal for investigation.

The three varieties of apatite at present known to occur in Cornwall are the sea-green limpid crystals from St. Michael's Mount and other places, the dirty-white, semi-opaque, hexagonal prisms associated with axinite from Botallack Head, and the thin hexagonal plates, described and analysed by Prof. Maskelyne and Dr. Flight as coming from a new locality, now known, however, to have been obtained by the late Mr. Tailing from Fowey Consols, and previously noted from this mine by Greg and Lettsom. To these must now be added a new variety which was lately brought to me as chalybite from the deep workings of Levant Mine, St. Just. The specimens are closely analogous to those analysed by Dr. Flight, but differ slightly in chemical composition and mode of occurrence.

Values of Δ2θ131-13̄1(Cu-Kα) have been determined for albites crystallized in the system NaAlSi3O8-β-LiAlSi2O6-H2O at various pressures, temperatures, and times. These values are consistently higher than those reported by MacKenzie (1957) for pure synthetic albites crystallized under similar conditions. Data of the present study have been combined with that of Stewart (1960) for albites crystallized in the system NaAlSi3O8-LiAlSiO4-H2O and, when plotted against bulk Li2O content, show constant Δ2θ131-13̄1 values at approximately 1·0 wt. % Li2O. The addition of Li to albites has a much more pronounced effect on the Δ2θ131-13̄1 parameter than the addition of K or Ca. Albites from lithium-rich pegmatites have much lower Δ2θ131-13̄1 values and are similar to those of synthetic low albites. The differences in this parameter between the natural and synthetic specimens are believed to be caused by differences in the structures of the coexisting lithium minerals in the natural and synthetic environments.

The mineral tacharanite has been recently re-examined by Cliff et al. (1975). They worked on material from the original locality, Portree, in Scotland (Sweet, I961) and from a few new European localities described between 1971 and 1974. None of the post-Sweet authors, however, refer to the second discovery of the mineral from Tasmania where it was identified by this writer in 1961 and recorded in a number of publications (Sutherland, 1965; Sutherland and Corbett, 1967; Sutherland and Hale 1970; Mines Department of Tasmania, 1970; Sutherland, 1973b). The first Tasmanian report was communicated to J. M. Sweet, who kindly arranged for the Department of Mineralogy, British Museum, to send the writer a small piece of the Portree material for study. As the Tasmanian find does not seem to be known in the later literature, some more detailed information on its occurrence is presented here for comparison with the European localities.

In the manganesiferous ores associated with the metacherts of the ophiolitic sequences at the Cerchiara mine, Eastern Liguria (Italy), a new Mn-bearing mineral belonging to the mica group has been recently found and characterized. High resolution transmission electron microscopy and electron diffraction tomography studies confirm that the mineral belongs to the mica group. Unit-cell parameters from the powder diffraction pattern are: a = 5.149(1), b = 8.915(1), c = 10.304(1) Å, β = 102.03(1)°, space group C2 or C2/m. On the basis of the electron paramagnetic resonance spectroscopic results, the Mn4+ content represents a very subordinate fraction of the total Mn, the remaining occurring as Mn3+. The Raman spectrum clearly indicates the presence of OH groups in the structure. Laser-ablation inductively-coupled-plasma mass-spectrometry measurements assess the presence of considerable amounts of Li.

Assuming all Mn as Mn3+ and 22 negative charges, the empirical formula can be expressed as: (K0.83□0.17)(Mn1.143+Mg0.80Li0.20Fe0.023+)(Si3.89Al0.10)O10[(OH)1.92F0.08] with the sum of the octahedral cations indicating a 'transitional' character between a di- and a tri-octahedral structure. This formula corresponds ideally to the Mn3+ analogue of celadonite, thus expanding the range of solid solution in the celadonite family. The ideal end-member formula KMn3+MgSi4O10(OH)2 can be easily related to celadonite by the homovalent substitution VIMn3+ → VIFe3+. The mineral and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association, (IMA 2015-052).

The separator here described was designed by the author some years ago in order to avoid the tedious process of hand-picking mineral powders in front of an electromagnet. It is a complete machine dealing on a laboratory scale with the less magnetic minerals, such as monazite. For research it is essential that the separation should be clean cut ; in the present case a 90% separation of glauconite from monazite can be made in a single pass, while the removal of more widely differing minerals is complete. The machine must also deal with small samples down to 0.5 gram without loss; this necessitates a small scale and slow feed ; the time required for more bulky samples is consequently rather long, but little or no attention is required during operation. Finally, all the moving parts should be of metal and easily cleaned.

To date, Fe-Li micas have been defined differently from other micas. The purpose of this paper is to reinterpret the actual Fe-Li mica series with new concepts of ‘essential replacement’ (the evolution direction) and ‘composition track’ (the sequence of mica varieties). Two hundred and fifty-eight analyses from the literature are used for this study in the form of eight data groups. The common compositional and substitutional characters of Fe-Li micas have been reinterpreted in light of principal component analysis and a geometric frame of ideal Fe2+-Al-Li micas in space with (Si, AlIV, AlVI, Fe2+, Li, ☐VI, K)-coordinates.

In our new interpretation, the actual Fe-Li micas are essentially neither AlIV- nor AlVI-, but ☐VI-constant. The actual Fe-Li micas are the weakest fluctuant relative to the Annite-Polylithionite-Trilithionite-Siderophyllite (APTE) plane. About 90% of variations of actual Fe-Li micas range from the trioctahedral trend described as a sequence along the segment K2Al2Fe5/22+Li☐1/2Si6Al2O20(OH,F)4+x[AlFe−22+Li3SiAl−2] (−1/3≤ x≤5/8). The substitution AlFe−22+Li3SiAl−2 (i.e. 2AlIV +4Fe2+ → 2Si +AlVI +3Li) is the main mechanism that keeps actual Fe-Li micas trioctahedral. More than 8% of variations arise from the dioctahedral trend involving created AlVI- and ☐VI-increasing replacement. The actual Fe-Li mica series comprises the composition trend from Fe2+-biotite to lepidolite. This series is not on the siderophyllite-polylithionite join, but can be expressed ideally as K2Al1+xFe4−4x2+Li1+3x(Si6+2xAl2−2x) O20(OH,F)4 (−1/3 ≤x≤1).

Holtite, approximately (Al,Ta,□)Al6(BO3)(Si,Sb3+,As3+)Σ3O12(O,OH,□s)Σ3, is a member of the dumortierite group that has been found in pegmatite, or alluvial deposits derived from pegmatite, at three localities: Greenbushes, Western Australia; Voron'i Tundry, Kola Peninsula, Russia; and Szklary. Lower Silesia, Poland. Holtite can contain >30 wt.% Sb2O3, As2O3, Ta2O5, Nb2O5, and TiO2 (taken together), but none of these constituents is dominant at a crystallographic site, which raises the question whether this mineral is distinct from dumortierite. The crystal structures of four samples from the three localities have been refined to R1 = 0.02—0.05. The results show dominantly: Al, Ta, and vacancies at the Al(l) position; Al and vacancies at the Al(2), (3) and (4) sites; Si and vacancies at the Si positions; and Sb, As and vacancies at the Sb sites for both Sb-poor (holtite I) and Sb-rich (holtite II) specimens. Although charge-balance calculations based on our single-crystal structure refinements suggest that essentially no water is present, Fourier transform infrared spectra confirm that some OH is present in the three samples that could be measured. By analogy with dumortierite, the largest peak at 3505-3490 cm-1 is identified with OH at the O(2) and O(7) positions. The single-crystal X-ray refinements and FTIR results suggest the following general formula for holtite: Al7-[5x+y+z]/3 (Ta,Nb)x□[2x+y+z]\3,BSi3-y(Sb,As)yO18-y-z(OH)z, where x is the total number of pentavalent cations, y is the total amount of Sb + As, and z ⩽ y is the total amount of OH. Comparison with the electron microprobe compositions suggests the following approximate general formulae Al5.83(Ta,Nb)0.50□0.67BSi2.50(Sb,As)0.50O17.00(OH)0.50 and Al5.92(Ta,Nb)0.25□0.83BSi2.00(Sb,As)1.00O16.00(OH)1.00 for holtite I and holtite II respectively. However, the crystal structure refinements do not indicate a fundamental difference in cation ordering that might serve as a criterion for recognizing the two holtites as distinct species, and anion compositions are also not sufficiently different. Moreover, available analyses suggest the possibility of a continuum in the Si/(Sb + As) ratio between holtite I and dumortierite, and at least a partial continuum between holtite I and holtite II. We recommend that use of the terms holtite I and holtite II be discontinued.

Calciodelrioite, ideally Ca(VO3)2(H2O)4, is a new mineral (IMA 2012-031) from the uraniumvanadium deposits of the eastern Colorado Plateau in the USA. The type locality is the West Sunday mine, Slick Rock district, San Miguel County, Colorado.The new mineral occurs on fracture surfaces in corvusite- and montroseite-impregnated sandstone and forms as a result of the oxidative alteration of these phases. At the West Sunday mine, calciodelrioite is associated with celestine, gypsum, huemulite, metarossite, pascoite and rossite. Themineral occurs as transparent colourless needles, bundles of tan to brown needles and star bursts of nearly black broad blades composed of tightly intergrown needles. Crystals are elongate and striated parallel to [100], exhibiting the prismatic forms {001} and {011} and having terminationspossibly composed of the forms {100} and {61}. The mineral is transparent and has a white streak, subadamantine lustre, Mohs hardness of about 2½, brittle tenacity, irregular to splintery fracture, one perfect cleavage on {001} and possibly one or more additional cleavages parallel to [100].Calciodelrioite is soluble in water. The calculated density is 2.451 g cm– 3. It is optically biaxial (+) with α = 1.733(3), β = 1.775(3), γ = 1.825(3) (white light), 2Vmeas = 87.3(9)° and 2Vcalc = 87°. The optical orientationis X = b; Z ≈ a. No pleochroism was observed. Electronmicroprobe analyses of two calciodelrioite samples and type delrioite provided the empirical formulae (Ca0.88Sr0.07Na0.04K0.01)Σ1.00(V1.00O3)2(H2.01O)4,(Ca0.76Sr0.21Na0.01)Σ0.98(V1.00O3)2(H2.01O)4 and (Sr0.67Ca0.32)Σ0.99(V1.00O3)2(H2.00O)4, respectively.Calciodelrioite is monoclinic, I2/a, with unit-cell parameters a = 14.6389(10), b = 6.9591(4), c = 17.052(2) Å, β = 102.568(9)°, V = 1695.5(3) Å3 and Z = 8. The seven strongest lines in the X-ray powder diffractionpattern [listed as dobs Å (I)(hkl)] are as follows: 6.450(100)(011); 4.350(16)(013); 3.489(18)(020); 3.215(17)(022); 3.027(50)(multiple); 2.560(28)(15,413); 1.786(18)(028). In the structure of calciodelrioite (refined to R1 = 3.14% for1216 Fo > 4σF), V5+O5 polyhedra link by sharing edges to form a zigzag divanadate [VO3] chain along a, similar to that in the structure of rossite. The chains are linked via bonds to Ca atoms, which also bond to H2Ogroups, yielding CaO3(H2O)6 polyhedra. The Ca polyhedra form a chain along b. Each of the two symmetrically independent VO5 polyhedra has two short vanadyl bonds and three long equatorial bonds. Calciodelrioite and delrioite are isostructuraland are the endmembers of the series Ca(VO3)2(H2O)4–Sr(VO3)2(H2O)4. Calciodelrioite is dimorphous with rossite, which has a similar structure; however, the smaller 8-coordinate Ca site in rossitedoes not accommodate Sr.

The associations hornblende and anthophyllite or cummingtonite are dealt with briefly in the light of experimental data and naturally occurring assemblages. On the basis of the distribution of Mg and Fe2+ in coexisting amphiboles and on the calculated and experimental slopes of a reaction in which the amphiboles hornblende and anthophyllite are formed a tentative P-T-x diagram is suggested for these parageneses.

Baumoite, Ba0.5[(UO2)3O8Mo2(OH)3](H2O)~3, is a new mineral found near Radium Hill, South Australia, where it occurs in a granite matrix associated with baryte, metatorbernite, phurcalite and kaolinite. Baumoite forms thin crusts of yellow to orange–yellow tabular to prismatic crystals. The mineral is translucent with a vitreous lustre and pale yellow streak. Crystals are brittle, the fracture is uneven and show one excellent cleavage. The Mohs hardness is ~2½. The calculated density is 4.61 g/cm3. Optically, baumoite crystals are biaxial (–), with α = 1.716(4), β = 1.761(4), γ = 1.767(4) (white light); and 2Vcalc = 42.2°. Electron microprobe analyses gave the empirical formula Ba0.87Ca0.03Al0.04U2.97Mo2.02P0.03O22H11.99, based on 22 O atoms per formula unit. The eight strongest lines in the powder X-ray diffraction pattern are [dobs Å (I) (hkl)]: 9.175(39)(12${\bar 1}$), 7.450(100)(020), 3.554(20)(221), 3.365(31)(004, 202), 3.255(31)(123, 30${\bar 2}$), 3.209(28)(12${\bar 4}$), 3.067(33)(30${\bar 3}$, 222, 32${\bar 2}$) and 2.977(20)(142). Single-crystal X-ray studies (R1 = 5.85% for 1892 main reflections) indicate that baumoite is monoclinic, superspace group X2/m(a0g)0s with X = (0,½,0,½), with unit-cell parameters: a = 9.8337(3), b = 15.0436(5), c = 14.2055(6) Å, β = 108.978(3)°, V = 1987.25(13) Å3 and Z = 4. The crystal structure is twinned and incommensurately modulated and is based upon sheets of U6+ and Mo6+ polyhedra of unique topology. Four independent cationic sites partially occupied by Ba atoms are located between the sheets, together with H2O molecules.

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.

The new mineral mauriziodiniite (IMA2019-036), NH4(As2O3)2I, was found at the Torrecillas mine, Iquique Province, Chile, where it is a secondary alteration phase associated with calcite, cuatrocapaite-(NH4), lavendulan, magnesiokoritnigite and torrecillasite on matrix consisting of native arsenic, arsenolite and pyrite. Mauriziodiniite occurs as hexagonal tablets up to ~300 μm in diameter. Crystals are colourless and transparent, with pearly to adamantine lustre and white streak. The Mohs hardness is ~1. Tablets are sectile and easily flexible, but not elastic. Fracture is curved, irregular and stepped. Cleavage is perfect on {001}. The calculated density is 3.916 g/cm3. Optically, mauriziodiniite is uniaxial (–) with ω = 2.07(calc) and ɛ = 1.770(5) (white light). The empirical formula, determined from electron microprobe analyses, is (NH4)0.94K0.03(As2O3)2I0.92Cl0.03. Mauriziodiniite is hexagonal, P6/mmm, a = 5.289(2), c = 9.317(2) Å, V = 225.68(18) Å3 and Z = 1. The structure, refined to R1 = 4.16% for 135 Io > 2σI reflections, contains three types of layers: (1) a planar neutral As2O3 (arsenite) sheet; (2) an NH4+ layer that links adjacent arsenite sheets via bonds to their O atoms; and (3) an I– layer that links adjacent arsenite sheets via bonds to their As atoms. The layer sequence is I–As2O3–NH4–As2O3–I. Mauriziodiniite is isostructural with lucabindiite and is structurally related to gajardoite, cuatrocapaite-(NH4), cuatrocapaite-(K) and torrecillasite.

Simple laboratory experiments involving the contact of distilled water with crushed olivine-basalt over several months under atmospheric temperature and pressure conditions have shown that constituents are dissolved from the basalt and upon evaporation the solutions deposit crystals of carbonates, smectites, and zeolites. The results bear out the observations and conclusions previously made in the field that solutions depositing secondary minerals in Tertiary basalts in New South Wales are extraneous and cold. It is also suggested that as the assemblage calcite-montmorillonite-heulandite can form in the vesicles of basalts under such conditions it should not be included in the zeolite facies of metamorphism.

The crystal structure of chenevixite, Cu2M2(AsO4)2(OH)4 (where M = Fe3+ or Al), pseudo-orthorhombic, monoclinic, a = 5.7012(8), b = 5.1801(7), c = 29.265(2) Å, β = 89.99(1)°, V = 864.3(4) Å3, space group B1211, Z = 4, was solved by direct methods and refined by least-squares techniques to R = 8.4% and a goodness-of-fit (S) of 1.37 for 1176 unique observed (F≥4σF) reflections collected for a twinned microcrystal using graphite-monochromated Mo-Kα X-rays and a CCD area detector. Vertex- and edge-sharing arsenate tetrahedra, Alϕ6 octahedra, and Jahn-Teller-distorted Cu2+ϕ6 octahedra [ϕ: O2−;, (OH)−;] form a framework unique from those in Cu2+ oxysalt minerals. Chains of edge-sharing Cu2+ϕ6 octahedra, with Alϕ6 octahedra attached on opposing sides by the sharing of edges, are linked into layers parallel to (001) by sharing vertices with AsO4 tetrahedra, and the layers are linked to form a frameworkby the sharing of polyhedral elements between adjacent Alϕ6 octahedra, as well as between AsO4 tetrahedra and Alϕ6 octahedra.

Kihlmanite-(Ce), Ce2TiO2[SiO4](HCO3)2(H2O), is a new rare-earth titanosilicate carbonate, closely related to tundrite-(Ce). It is triclinic, P, a = 4.994(2), b = 7.54(2), c = 15.48(4) Å, α = 103.5(4), β = 90.7(2), γ = 109.2(2)o , V = 533(1) Å3, Z = 2 (from powder diffraction data) or a = 5.009(5), b = 7.533(5), c = 15.407(5) Å, α = 103.061(5), β = 91.006(5), γ = 109.285(5)°, V = 531.8(7) Å3, Z = 2 (from single-crystal X-ray diffraction data). The mineral was found in the arfvedsonite-aegirine-microcline vein in fenitized metavolcanic rock at the foot of the Mt Kihlman (Chil’man), near the western contact of the Devonian Khibiny alkaline massif and the Proterozoic Imandra-Varzuga greenstone belt. It forms brown spherulites (up to 2 cm diameter) and sheaf-like aggregates of prismatic crystals, flattened on {010} and up to 0.5 mm diameter. Both spherulites and aggregates occur in interstices in arfvedsonite and microcline, in intimate association with golden-green tundrite-(Ce). Kihlmanite-(Ce) is brown, with a vitreous lustre and a pale yellowish-brown streak. The cleavage is perfect on {010}, parting is perpendicular to c and the fracture is stepped. Mohs hardness is ∼3. In transmitted light, the mineral is yellowish brown; pleochroism and dispersion were not observed. Kihlmanite-(Ce) is biaxial (+), α = 1.708(5), β = 1.76(1), γ = 1.82(1) (589 nm), 2Vcalc = 89°. The optical orientation is Y ^ c = 5°, other details are unclear. The calculated and measured densities are 3.694 and 3.66(2) g cm−3, respectively. The mean chemical composition, determined by electron microprobe, is: Na2O 0.13, Al2O3 0.24, SiO2 9.91, CaO 1.50, TiO2 11.04, MnO 0.26, Fe2O3 0.05, Nb2O5 2.79, La2O3 12.95, Ce2O3 27.33, Pr2O3 2.45, Nd2O3 8.12, Sm2O3 1.67, Gd2O3 0.49 wt.%, with CO2 15.0 and H2O 6.0 wt.% (determined by wet chemical and Penfield methods, respectively), giving a total of 99.93 wt.%. The empirical formula calculated on the basis of Si + Al = 1 atom per formula unit is (Ca0.16Na0.11Mn0.02)∑0.29[(Ce0.98La0.47Pr0.09Nd0.29Sm0.06Gd0.02)∑1.91(Ti0.82Nb0.12)∑0.94O2 (Si0.97Al0.03)∑1O4.02(HCO3)2.01](H2O)0.96. The simplified formula is Ce2TiO2(SiO4)(HCO3)2·H2O. The mineral reacts slowly in cold 10% HCl with weak effervescence and fragmentation into separate plates. The strongest X-ray powder-diffraction lines [listed as d in Å(I) (hkl)] are as follows: 15.11(100)(00), 7.508(20)(00), 6.912(12)(01), 4.993(14)(00), 3.563(15)(01), 2.896(15)(1). The crystal structure of kihlmanite-(Ce) was refined to R1 = 0.069 on the basis of 2441 unique observed reflections (MoKα, 293 K). It is closely related to the crystal structure of tundrite-(Ce) and is based upon [Ce2TiO2(SiO4)(HCO3)2] layers parallel to (001). Kihlmanite-(Ce) can be considered as a cationdeficient analogue of tundrite-(Ce). The mineral is named in honour of Alfred Oswald Kihlman (1858–1938), a remarkable Finnish geographer and botanist who participated in the Wilhelm Ramsay expeditions to the Khibiny Mountains in 1891–1892. The mineral name also reflects its occurrence at the Kihlman (Chil’man) Mountain.