The crystal structure and chemical formula of zvyaginite, ideally Na2ZnTiNb2(Si2O7)2O2(OH)2(H2O)4, a lamprophyllite-group mineral of the seidozerite supergroup from the type locality, Mt. Malyi Punkaruaiv, Lovozero alkaline massif, Kola Peninsula, Russia have been revised. The crystal structurewas refined with a new origin in space group C1, a = 10.769(2), b = 14.276(3), c = 12.101(2) Å, α = 105.45(3), β = 95.17(3), γ = 90.04(3)°, V = 1785.3(3.2) Å3, R1 = 9.23%. The electron-microprobe analysis gave the following empirical formula [calculated on 22 (O + F)]: (Na0.75Ca0.09K0.04□1.12)Σ2 (Na1.12Zn0.88Mn0.17Fe2+0.04□0.79)Σ3 (Nb1.68Ti1.25Al0.07)Σ3 (Si4.03O14)O2 [(OH)1.11F0.89]Σ2(H2O)4, Z = 4. Electron-diffraction patterns have prominent streaking along c* and HRTEM images show an intergrowth of crystalline zvyaginite with two distinct phases, both of which are partially amorphous. The crystal structure of zvyaginite is an array of TS (Titanium-Silicate) blocks connected via hydrogen bonds between H2O groups. The TS block consists of HOH sheets (H = heteropolyhedral, O = octahedral) parallel to (001). In the O sheet, the [6]MO(1,4,5) sites are occupied mainly by Ti, Zn and Na and the [6]MO(2,3) sites are occupied by Na at less than 50%. In the H sheet, the [6]MH(1,2) sites are occupied mainly by Nb and the [8]AP(1) and [8]AP(2) sites are occupied mainly by Na and □. The MH and AP polyhedra and Si2O7 groups constitute the H sheet. The ideal structural formula is Na□Nb2NaZn□Ti(Si2O7)2O2(OH)2(H2O)4. Zvyaginite is a Zn-bearing and Na-poor analogue of epistolite, ideally (Na□)Nb2Na3Ti(Si2O7)2O2(OH)2(H2O)4. Epistolite and zvyaginite are related by the following substitution in the O sheet of the TS-block: (Naþ 2 )epi↔Zn2+ zvy +□zvy. The doubling of the t1 and t2 translations of zvyaginite relative to those of epistolite is due to the order of Zn and Na along a (t1) and b (t2) in the O sheet of zvyaginite.

The high-pressure monazite – scheelite structure transition has been observed at P >4.57 GPa in CaSeO4 by synchrotron X-ray powder diffraction. It is a first-order transition with a 4.5% volume change and is severely hindered kinetically. Scheelite-type CaSeO4 remains to a maximum experimental pressure of 42.2 GPa and no (002) reflection, specifically indicative of a subgroup transition to a fergusonite-type structure, is observed. Scheelite-type CaSeO4 remains at ambient conditions, where the tetragonal unit cell has parameters of a = 5.04801(11) c = 11.6644(5) Å and V = 297.21(3) Å3 with Dcalc = 4.090 g cm–3. The diffraction pattern of the recovered material was refined in space group I41/a to Rp = 0.98%, wRp = 1.91%, GoF = 0.59, RFobs = 5.04%, wRFobs = 4.27%. The oxygen is located on the general 16f site at (0.2578(8) 0.3699(14) 0.5755(4)) and shares four identical bonds with Se (4a: ½ ½ ½) at 1.644(5) Å. The Ca (4b: 0, 0, ½) is eight-coordinated via O at 4 × 2.440(6) Å and 4 × 2.504(5) Å. This is further evidence of the dissimilarity of sulfate and selenate at high pressure and temperature conditions and the closer resemblance of the selenates to the orthophosphates, arsenates and vanadates, where this type of transition sequence has been described.

The new mineral joanneumite was found at Pabellón de Pica Mountain, Iquique Province, Tarapacá Region, Chile, where it occurs as violet microcrystalline aggregates up to 2 mm in size in small cracks in a gabbroic rock, which is covered by a guano deposit. Associated minerals are salammoniac, dittmarite, möhnite and gypsum. Joanneumite is non-fluorescent and the Mohs hardness is 1. The calculated density is 2.020 g cm–3. The infrared spectrum of joanneumite shows the frequencies of NH3 and isocyanurate groups and the absence of absorptions of H2O molecules and OH– ions. The chemical composition (electron microprobe data, the hydrogen was calculated from the structural formula, wt.%) is C 20.33, N 31.11, O 28.34, Cu 17.27, Zn 0.24, H 2.82, total 100.11. The empirical formula is Cu0.96Zn0.01N7.84C5.98O6.25H9.96 and the idealized formula is CuN8C6O6H10 with the structural formula Cu(C3N3O3H2)2(NH3)2. Due to the lack of suitable single crystals the synthetic analogue of joanneumite was prepared for the single-crystal structure refinement. The crystal structure was solved and refined to R = 0.025 based upon 1166 unique reflections with I > 2σ (I). Joanneumite is triclinic, space group P1̄, a = 4.982(1), b = 6.896(1), c = 9.115(2) Å, α = 90.53(3), β = 97.85(3), γ = 110.08(3)°, V = 290.8(1) Å3, Z = 1 obtained from single-crystal data at 100 K, which are in good agreement with cell parameters from powder diffraction data of joanneumite at 293 K: a = 5.042(1), b = 6.997(1), c = 9.099(2) Å, α = 90.05(3), β = 98.11(2), γ = 110.95(3)° and V = 296.3(1) Å3. The eight strongest lines of the powder X-ray diffraction pattern are [d, Å (I,%) (hkl)] 6.52 (68) (010), 5.15 (47) (011), 4.66 (21) (100, 110), 4.35 (9) (1̄11), 3.29 (6) (1̄20), 3.22 (7) (1̄1̄1), 3.140 (100) (1̄21), 2.074 (7) (1̄32). The crystal structure of joanneumite is identical with the structure of synthetic bis(isocyanurato) diamminecopper(II).

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.

The new mineral feynmanite, Na(UO2)(SO4)(OH)·3.5H2O, was found in both the Blue Lizard and Markey mines, San Juan County, Utah, USA, where it occurs as a secondary phase on pyrite-rich asphaltum in association with chinleite-(Y), gypsum, goethite, natrojarosite, natrozippeite, plášilite, shumwayite (Blue Lizard) and wetherillite (Markey). The mineral is pale greenish yellow with a white streak and fluoresces bright greenish white under a 405 nm laser. Crystals are transparent with a vitreous lustre. It is brittle, with a Mohs hardness of ~2, irregular fracture and one perfect cleavage on {010}. The calculated density is 3.324 g cm–3. Crystals are thin needles or blades, flattened on {010} and elongate on [100], exhibiting the forms {010}, {001}, {101} and {10$\bar{1}$}, and are up to ~0.1 mm in length. Feynmanite is optically biaxial (–), with α = 1.534(2), β = 1.561(2) and γ = 1.571(2) (white light); 2Vmeas. = 62(2)°; no dispersion; and optical orientation: X = b, Y ≈ a,Z ≈ c. It is weakly pleochroic: X = colourless, Y = very pale green yellow and Z = pale green yellow (X < Y < Z). Electron microprobe analyses (WDS mode) provided (Na0.84Fe0.01)(U1.01O2)(S1.01O4)(OH)·3.5H2O. The five strongest powder X-ray diffraction lines are [dobs Å(I)(hkl)]: 8.37(100)(010), 6.37(33)($\bar{1}$01,101), 5.07(27)($\bar{1}$11,111), 4.053(46)(004,021) and 3.578(34)(120). Feynmanite is monoclinic, has space group P2/n, a = 6.927(3), b = 8.355(4), c = 16.210(7) Å, β = 90.543(4)°, V = 938.1(7) Å3 and Z = 4. The structure of feynmanite (R1 = 0.0371 for 1879 Io > 2σI) contains edge-sharing pairs of pentagonal bipyramids that are linked by sharing corners with SO4 groups, yielding a [(UO2)2(SO4)2(OH)2]2– sheet based on the phosphuranylite anion topology. The sheet is topologically identical to those in deliensite, johannite and plášilite. The dehydration of feynmanite to plášilite results in interlayer collapse involving geometric reconfiguration of the sheets and the ordering of Na.

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.

Fluorcaphite [SrCaCa3(PO4)3F] is a rare strontium-calcium member of the apatite supergroup which was previously known only from the Khibiny and Lovozero alkaline complexes. This paper presents evidence of a third fluorcaphite occurrence. It was found in hydrothermally altered Lower Cretaceous teschenite, which forms an intrusive body (probably a sill) in the Lower Cretaceous siliciclastic flysch sediments at Tichá near Frenštát pod Radhoštěm, Silesian Unit, Outer Western Carpathians (Czech Republic). Fluorcaphite occurs as an accessory mineral in hydrothermal veins and in an adjacent alteration zone within the host teschenite. Vein-hosted fluorcaphite forms euhedral crystals and skeletal crusts enclosed in analcime while the teschenite-hosted fluorcaphite forms small overgrowths on older phenocrysts of magmatic apatite. Fluorcaphite from Tichá contains 0.50–1.97 Sr apfu, 2.96–4.49 Ca apfu, 0.59–1.09 F apfu and significantly lower Na (0.01–0.05 apfu) and LREE contents (up to 0.07 apfu). Fluorcaphite formed under hydrothermal conditions after solidification of the host teschenite during post-magmatic hydrothermal activity at temperatures probably between ∼150 and 300°C. The initial 87Sr/86Sr ratio of vein-hosted analcime +fluorcaphite (0.7063) is significantly higher than those of the host teschenite (0.7041). We therefore suggest a mix of strontium sources in the vein analcime+fluorcaphite: (1) from the host teschenite plus (2) from external source(s) including the Lower Cretaceous seawater and/or surrounding sedimentary rocks of the Silesian Unit. These data indicate an open-system fluid regime and the participation of various fluid sources during the alteration event giving rise to fluorcaphite.

The mineral truscottite was discovered at the Lebong Donok mine, Benkulen, Sumatra, by Hövig in 1914. He considered it to be a hydrated calcium silicate of composition CaO.2SiO2.1/2H2O. Later work by Grutterink suggested a different formula, 2(Ca,Mg)O.3SiO2.2H2O, the water content being reduced to 1-3 molecules after drying at 120°. Grutterink noted that the composition, general character, and optical properties indicated a similarity to gyrolite. Flint, McMurdie, and Wells concluded from X-ray powder photographs that the two species were identical, although they detected quartz as an impurity in the truscottite examined. All known specimens of truscottite come from the original locality, and no further investigations have been reported.

Hundholmenite-(Y) occurs as pale brown, subhedral crystals up to 1 mm across, embedded in REE–bearing fluorite, in a granitic pegmatite at Hundholmen, Tysfjord, Nordland County, north Norway. Two other occurrences in the same area are the granitic pegmatites at Stetind and Lagmannsvik. The simplified formula, obtained from wavelength-dispersive EMP analyses and boron determination by ICP-AES, is (Y,REE,Ca,Na)15(Al,Fe3+)CaxAs1–x3+ (Si,As5+)Si6B3(O,F)48 (x = 0.78). The mineral is trigonal, R3m, with a = 10.675(6), c = 27.02(2) Å , V = 2667(5) Å 3, Z = 3. The crystal structure was refined to R1 = 0.037 for 1720 observed reflections. Hundholmenite-(Y) is isostructural with okanoganite-(Y) and vicanite-(Ce), and the differences in site populations are discussed. The strongest seven reflections of the X-ray powder-diffraction pattern [dobs in Å , (I) (hkl)] are: 4.38 (33) (202), 3.114 (43) (214), 2.972 (100) (027), 2.947 (76) (125), 2.924 (66) (303, 033), 2.681 (36) (220) and 1.978 (37) (235). The mineral is optically uniaxial (–) with o 1.7578(5) and e 1.7487(5). The Mohs hardness is ~5–6; Dcalc = 5.206(9) g/cm3.

The new mineral oskarssonite (IMA2012-088), with ideal formula AlF3, was found in August 2009 at the surface of fumaroles on the Eldfell volcano, Heimaey Island, Iceland (GPS coordinates 63°25′58.9″N 20°14′50.3″W). It occurs as sub-micron-sized crystals forming a white powder in association with anhydrite, bassanite, gypsum, jarosite, anatase, hematite, opal, ralstonite, jakobssonite and meniaylovite. Chemical analyses by energy-dispersive spectrometry with a scanning electronmicroscope produced the following mean elemental composition: Al, 31.70; F, 58.41; O, 9.22; total 99.33 wt.%. The empirical chemical formula is AlF2.6(OH)0.5 which suggests partial substitution of F by OH. Oskarssonite is rhombohedral, space group Rc, with ah = 4.9817(4) Å, c = 12.387(1) Å, Vuc = 266.23(5) Å3, Z = 6. The five strongest lines in the powder diffraction diagram [d in Å(I) (hkl)] are as follows: 3.54 (100) (012), 2.131 (13) (113), 1.771 (20) (024), 1.59 (15) (116), 1.574 (10) (122). Rietveld refinement confirms the identity of oskarssonite with the synthetic rhombohedral form of AlF3. Its structure can be described as a rhombohedral deformation of the idealized cubic perovskitetype octahedral framework of corner-sharing AlF6 groups. Oskarssonite appears in the surface part of the fumaroles where fluorides are abundant. At greater depths (below 10 cm) sulfates dominate among the fumarolic minerals. In accordance with its occurrence, we surmise that oskarssonite forms in the later stages of the fumarolic activity in an environment poor in alkalies and Mg. Ralstonite (NaxMgxAl1−xF3(H2O)y), which, unlike oskarssonite, contains Na and Mg as important constituents, dominated in the first-formed fumaroles, but now, 41 years after the eruption of Eldfell, is only a minor phase. The new mineral is named after the Icelandic volcanologist Niels Oskarsson.

Chemical analyses of nine K-feldspars and thirteen albites, along with their optical, physical, and X-ray data are presented. The obliquity values Δ = 12·5(d131-d13¯1) of the K-feldspars are found to be independent of the contents of silica and volatiles in the rocks. The role of temperature as the primary factor affecting the obliquity values is stressed. The relationship between the (An + Ab) content of the potassic phase of K-feldspars and 2Vα is shown diagrammatically.

Camaronesite (IMA 2012-094), [Fe3+(H2O)2(PO3OH)]2(SO4)·1–2H2O, is a new mineral from near the village of Cuya in the Camarones Valley, Arica Province, Chile. The mineral is a low-temperature, secondary mineral occurring in a sulfate assemblage with anhydrite, botryogen, chalcanthite, copiapite, halotrichite, hexahydrite, hydroniumjarosite, pyrite, römerite, rozenite and szomolnokite. Lavender-coloured crystals up to several mm across form dense intergrowths. More rarely crystals occur as drusy aggregates of tablets up to 0.5 mm in diameter and 0.02 mm thick. Tablets are flattened on {001} and exhibit the forms {001}, {104}, {015} and {018}. The mineral is transparent with white streak and vitreous lustre. The Mohs hardness is 2½, the tenacity is brittle and the fracture is irregular, conchoidal and stepped. Camaronesite has one perfect cleavage on {001}. The measured and calculated densities are 2.43(1) and 2.383 g/cm3, respectively. The mineral is optically uniaxial (+) with ω = 1.612(1) and ε = 1.621(1) (white light). The pleochroism is O (pale lavender) > E (colourless). Electron-microprobe analyses provided Fe2O331.84, P2O529.22, SO315.74, H2O 23.94 (based on O analyses), total 100.74 wt.%. The empirical formula (based on 2 P a.p.f.u.) is: Fe1.94(PO3OH)2(S0.96O4)(H2O)4·1.46H2O. The mineral is slowly soluble in concentrated HCl and extremely slowly soluble in concentrated H2SO4. Camaronesite is trigonal, R32, with cell parameters:a = 9.0833(5), c = 42.944(3) Å, V = 3068.5(3) Å3 and Z = 9. The eight strongest lines in the X-ray powder diffraction pattern are [dobs Å (I)(hkl)]: 7.74(45)(101), 7.415(100)(012), 4.545(72)(110), 4.426(26)(018), 3.862(32)(021,202,116), 3.298(93)(027,119), 3.179(25)(208) and 2.818(25)(1·1·12,125). In the structure of camaronesite (R1 = 2.28% for 1138 Fo > 4σF), three types of Fe octahedra are linked by corner sharing with (PO3OH) tetrahedra to form polyhedral layers perpendicular to c with composition [Fe3+(H2O)2(PO3OH)]. Two such layers are joined through SO4 tetrahedra (in two half-occupied orientations) to form thick slabs of composition [Fe3+(H2O)2(PO3OH)]2(SO4). Between the slabs are partially occupied H2O groups. The only linkages between the slabs are hydrogen bonds. The most distinctive component in the structure consists of two Fe octahedra linked to one another by three PO4 tetrahedra yielding an [Fe2(PO4)3] unit. This unit is also the key component in the sodium super-ionic conductor (NASICON) structure and has been referred to as the lantern unit. The polyhedral layers in the structure of camaronesite are similar to those in the structure of taranakite. The Raman spectrum exhibits peaks consistent with sulfate, phosphate, water and OH groups.

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.

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.

In Part I (Vinograd, 2002) the relationship between temperature, composition and free energy of the diopside–jadeite solid solution was described using a CVM model. Here the same relationship is described using a combination of Redlich-Kister (RK) polynomials and Gaussian functions. The use of the Gaussians permits an accurate description of the free energy dip centred at Jd50, which is caused by the long-range ordering, while the effect of the short-range ordering can be easily modelled using the RK polynomial The simplified RK-Gaussian description is extended to the three-component diopside–jadeite–hedenbergite solid solution. The polynomial description permits an easy incorporation of the derived activity-composition relations into phase-equilibrium computation software.

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.

Pyrrhotite Fe1–xS is the main sulfide component of platinum-group element (PGE) ores and commonly contains from a few tenths to a few dozen ppm of disseminated Pt. Here we report an X-ray absorption spectroscopy investigation into the state of Pt in synthetic pyrrhotite in combination with theoretical spectra modelling. The pyrrhotite crystals were obtained by means of the salt flux technique, using a eutectic mixture of alkali metal halides as the transport media. Analysis of the chemical composition of synthesised crystals showed that an increase of the temperature and sulfur fugacity yields higher concentrations of Pt in pyrrhotite. The Pt content reached 0.6 wt.% at the maximum temperature and sulfur fugacity (t = 720°C, log $f_{{\rm S}_ 2}$ = –0.1) achieved in a Pt-saturated system. X-ray absorption near-edge structure (XANES) analysis of Pt L3-edge spectra revealed that Pt is present in pyrrhotite in the 4+ and 2+ ‘formal’ oxidation states. Theoretical modelling of XANES and interpretation of extended X-ray absorption fine structure (EXAFS) spectra showed that Pt4+ substitutes for Fe in the crystal lattice of pyrrhotite, whereas Pt2+ forms PtS-like clusters disseminated in the pyrrhotite matrix. Atoms of isomorphous Pt4+ are surrounded by 6 S atoms at a distance of 2.39 ± 0.02 Å. According to theoretical simulations using the FDMNES program, the second coordination sphere of the solid-solution Pt contains one vacancy in the Fe sublattice within the Fe-layer. The Pt2+S-like clusters can be considered as a quench product. High sulfur fugacity stabilises the solid-solution Pt and prevents the formation of the PtS-like clusters during cooling. The maximum content of the solid-solution Pt in pyrrhotite is ca. 50 times lower than in pyrite and can be approximated by a straight line in the log C(Pt) vs. 1/T plot, it increases from 1 ppm at 350°C to 3 wt.% at 900°C.