We performed Cs-adsorption experiments using actual soil from paddy field, Iitate-mura, Fukushima and identified clay minerals which most effectively adsorbed Cs, using EPMA, SEM-EDS, FIB and TEM-EDS. EPMA chemical mapping showed that Cs was adsorbed inhomogeneously in the soil pellets. A sequence of analyses revealed that vermiculite and iron-rich smectite adsorbed the highest concentration of Cs (vermiculite is higher). On the other hand, kaolin minerals which are the most abundant clay minerals in the soil and muscovite/illite apparently did not adsorb Cs.

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Based on fundamental experiments, interaction between Cs and minerals,organic matters & microbes, and its possible recirculation by diffusion and concentration in the environment was discussed.

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Behaviour of Cs in the environment  was  descussed based on absorption properties of plants and clay minerals : Especially, different mechanism for various plant leaves was suggested.

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New idea and technique for disposal of toxic compounds and heavy metals (including radioactive nuclear wastes) which are used to be solidified wastes as stopped cyclic process in limited places of interior or storages, are proposed in this study as dynamic material changes of three VLS states including light elements (with carbon-bearing compounds etc.) which can be obtained in cyclic system of active Earth with long activity records.

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X-ray computed tomography (CT) apparatus is a useful tool to obtain three-dimensional distribution of the density and composition in the complex and heterogeneous geo-materials for the water-rock interaction study. This is a brief introduction of X-ray CT, and the principle, case study and some remarks will be presented.

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We have examined lower crustal and uppermost mantle xenoliths from the Ichinomegata Maar and found the characteristic microtopography of two dimensional crystal surfaces such as growth steps, growth hills and etch pits. We also found by using an X-ray micro tomography that two dimensional, film-shaped pores are common, especially in the interphase boundaries, and that they are well interconnected. These observations show that interconnected fluid films exist in the lower crust and uppermost mantle, being responsible for the high electrical conductivity that was required from MT observations.

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Quartz crystal is rare in space, whereas there is quartz on the earth in large quantities. This difference comes from existence of the water on the earth.

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Oxygen isotopic compositions of granitoids of Tanohata zoned pluton, associated satellite granitoid bodies and pelitic metamorphic rocks were investigated to elucidate isotopic natures of fluid in equilibrium with these silicate rocks. Pelitic hornfels and migmatite formed at higher temperatures than the hornfels show systematically different isotopic ratios, indicating that they were under different fluid systems at the time of contact metamorophism. The role of partial melt could be important in separating these two fluid systems, by absorbing and buffering oxygen isotope ratios between granitoids and metasediments.

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We observe the microstructures of slickenside of faulted cherts that are composed of Jurassic and Jurassic-Cretaceous accretionary complexes, in order to clarify generation mechanism of slickenside. Our results are 1) The trigger of faulting in chert blocks is generation of weak plane created by pressure solution. 2) Slickenside is an amorphous thin layer with 50 nm – 100 nm in width, which is composed of very tiny grains with less than 50 nm in size. These grains are amorphous materials mainly with quartz composition.

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Veins are defined as mineral aggregates that precipitated from a geofluid. Veins, including igneous dikes, have two meanings for  understanding the Earth processes. One is mineral aggregate and mineral assemblages which could indicate multi-component equilibrium and kinetics of geofluids, and another one is failure of the Earth’s crust.Fluids has great role to create fracture networks as an explosive failure. Recent progress in field observational, experimental and theoretical research concerning "Hydrothermal Brecciation" and "Hydrothermally Derived Fracturing" will be presented.

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Hot Dry Rock geothermal system can produce energy from previously unusable site, which does not require natural convective hydrothermal resources, and therefore it has large potential as a sustainable power generation. In this system, artificial reservoir is produced by hydro-fracturing in the basement due to water injection, and then water travels through fractures in the rock and inject back into the ground. To test time-scale of water circulation in this system, we investigate porosity and permeability changes during fracture experiments in the laboratory. 

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It is considered to be difficult to precipitate calcite in reasonable timescale for carbon storage. In contrast, calcite veins are common in natural geological settings. The purpose of this study is to understand the mechanism of calcite precipitation in hydrothermal environments. The leaching experiments revealed that several cations were leached from the rocks, resulting in alkaline fluids supersaturated with calcite. The flow-through experiments revealed that the acidic solution made by CO₂ bubbling was undersaturated with calcite. Alkaline fluids with NaHCO₃ reacted with pelitic rocks to produce calcite crystals with size of 0.01 mm precipitated on the calcite substrates.

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Spectroscopic measurements in the range from 350 nm to 1050 nm for pure H₂O, CO₂ and C₂H₅OH fluids under high temperatures and pressures were carried out to observe critical phenomena by using visible-type autoclave. Intensity of transmitted light though the fluid became low drastically around the critical point in both cases of H₂O and C₂H₅OH. Intensity of transmitted light through CO₂ was very low under subcritical condition and was high in supercritical region. Differences between experimentally determined critical temperature and reference data in literature of pure fluids were within ca. 1.6°C, and pressure differences were less than 0.3 MPa.

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Amorphous nanoparticles on the slip surface have been paid much attention since they give significant influences on the frictional properties. They are considered to be formed by combined processes including mechanical, chemical and thermal ones. It is well known that clay minerals are easily transformed into amorphous materials mechanochemically by grinding. We performed experimental studies on amorphization of clay minerals including kaolinite and saponite.

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Pelitic gneisses with Cl-rich biotite included in garnet are linearly distributed for 200 km long in the Sor Rondane Mountains. The condition of Cl-rich fluid infiltration is estimated to be ca. 800 oC, 8 kbar at 600 Ma. Garnet in this sample has core-rim boundary defined by P-zoning, rim formation being contemporaneous with the Cl-rich fluid infiltration. The garnet core includes monazite, and the rim includes xenotime and coarse-grained zircon. This suggests that originally LREE-rich mineral assemblage changed to HREE- and Zr-rich ones, because of Cl-rich fluid infiltration. Further study is needed to account for the mechanism of this process.

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Clintonite-bearing metasomatic veins were found from the contact aureole of the Kaizukiyama granite, Kasuga area, Japan. The veins are symmetrically zoned with the following sequence of mineral assemblages from the host rock (dolomitic marble) to the vein center; Zone1: diopside + forsterite + calcite, Zone2: clintonite + spinel + pargasite + diopside, and Zone3: grossular + diopside + clinozoisite + anorthite + adularia + calcite. Zone1 and Zone2 were formed essentially by SiO₂ metasomatism and Al₂O₃ metasomatism, respectively.  

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In order to obtain the hydration rates of peridotites under mantle wedge conditions, we have conducted the hydration experiments using the piston–cylinder apparatus at 580°C and 1.3 GPa. The reaction was not clearly discernible in olivine powder. In contrast, olivine in lherzolite powder was reacted with SiO₂ released during orthopyroxene alteration. The obtained conversion degrees were fitted using the Avrami equation. Then, we got the apparent growth velocity G ~ 1μm/day. Comparing the G value with the porous flow velocities, it is inferred that the mostly complete hydration reaction will be established in the slow porous flow.

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Nano-thickness thin film water between amphibole crystal surfaces were investigated using molecular dynamics simulations.  MXDORTO/MXDTRICL system was used thoughout in this study with the interatomic potential model of water and of newly developed one for amphibole.  Under the boundary conditions of three dimensional periodic repeations, the oposite planes of tremolite surface are both (110) plane and the same direction.  The structure of film water, diffusivity, viscosity, etc. were investigated.

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Dynamic material changes by three vapor-liquid-solid (VLS) states of impact and volcanic processes can be explained in water and solid changes at water planet Earth. However, on the present new model of the dynamic VLS cyclic process, the waterless extraterrestrial bodies of the Earth-type planets and the Moon reveal similar dynamic VLS material changes by impacts and volcanic uplift process. The present global model of the dynamic VLS changes suggests that any disposal of waste products on our life activities should be re-used, where cyclic stopped methods (especially heavy metals) becomes serious problems on active Earth and our life activities.

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We investigate chemical compositions of fluid inclusions in amphibole-bearing spinel-plagioclase lherzolite xenoliths of the Ichinomegata volcano, northeast Japan arc. The fluid inclusions are composed of CO₂–H₂O–Cl–S fluids. The salinity of fluid inclusions is 0.18–0.35 and 3.7 wt% NaCl equivalent. Assuming that these fluid inclusions have originated from a vapor-saturated basaltic magma, H₂O and CO₂ contents of the magma coexisting with the fluids preserved as fluid inclusions are 2.9–5.3 wt% H₂O and 0.7–0.8 wt% CO₂, respectively. The Cl content of the magma is 0.02–0.05 wt%.

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The origin of historic potassic basalts (from the 1719–1721 AD eruption) from the Wudalianchi volcanic field, northeast China, is investigated. The samples contain ~5 vol.% olivine microphenocrysts, and are characterized by K₂O enrichment (>4 wt.%) and an EM1-like isotopic signature. By using thermodynamic calculations with the observed petrological features of the basalts, the eruption temperatures of the magmas are estimated to have been about 1250–1260°C. Because the estimated temperatures are significantly higher than the estimated maximum temperature of the lithospheric mantle beneath the Wudalianchi volcanic field, the magmas have plausibly been derived from the asthenospheric mantle. We suggest that both the potassic- and EM1-like natures of the basalts originated from the mantle transition zone which was metasomatized by K-rich sediment fluids at ~1.5 Ga ago through a stagnation of an ancient slab. We infer that the Wudalianchi magmatism was caused by an upwelling of a hydrous mantle plume from the mantle transition zone which has been remarkably hydrated through stagnation of the ancient subducted slab and the recent Pacific slab.

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The melting conditions have been estimated inversely by optimizing the predicted magma composition to the observed composition of volcanic rock, with the two parameters: melting degree and the proportion of spinel- and garnet-lherzolite involved in melting. Consequently, the low melting degree of dominantly garnet-lherzolite with a high fluid flux from the two slabs beneath central Japan has been argued to be responsible for compositional characteristics, including the adakitic signatures, of the studied rocks. These results imply that the geochemical approach may provide a useful constrain to the P-T condition in the mantle wedge to constrain the geothermal structure in subduction zones.

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We analyzed OH concentration of plagioclase inMORB from Indian Ocean to constrain partitioning of H between plagioclase and low-H₂O basaltic melt. The OH concentration of plagioclase was ≤ 60 wt. ppm H₂O and H₂O concentration of plagioclase-hosted melt inclusions was ≈0.05 wt.%. As a result, partition coefficient of H between plagioclase and basaltic melt is ≈ 0.1 in molar basis under almost dry conditions. This analytical result is consistent with our previous experiments on hydrogen partitioning between plagioclase and H₂O-undersaturated melt, where partition coefficient is highest under almost dry conditnin and monotonously decreases with increasing H₂O in melt. 

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We studied water content in basalt magma from Izu-oshima, Miyakejima and Fuji volcanoes, based on petrology, OH in minerals, melt inclusions and experimental constrints on magma chambers, etc. We found that arc tholeiite basalt magma contains 3-5 wt% of water at crustal magma chamber depper than 10 km beneath these volcanoes. We show that changing lithology, fractionation trends and style of volcanic activity are largely controlled by the water content and the mode of degassing from the magma.

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Fe³⁺/ΣFe ratios were measured for quenched boninitic and basaltc glasses erupted at the early stage of Ogasawara arc formation by using Fe-K edge micro-XANES spectroscopy. Boninitic and basaltic glasses showed Fe³⁺/ΣFe ratios of 0.2-0.25 and 0.18-0.22, which correspond to ΔQMF values [=log fO₂ - log fO₂ (QMF)] of 1-1.7 and 0.6-1.2, respectively; the boninitic glasses were slightly more oxidized than the basaltic ones. ΔQMF values inferred for their primary melts were almost identical; 0.4-1.1 and 0.4-0.8, respectively, which are more oxidized than MORB glasses. We will discuss about fO₂ development process of arc mantle based on the present results.

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Pyrrhotite (Po) in the pumice from the Sakurajima Taisho eruption is sometimes partly reacted to form spongy Fe oxides. EPMA analyses revealed that they are mostly magnetite. Even in the outermost rim, they contain no Ti, showing that the spongy magnetite contacted with melt in less than 4 h before quenching. Thermodynamic calculations showed that the upper limit of the Po–stable f_O2 is NNO +2.6 log unit at magmatic temperature. These observations indicate that the reaction was caused at a shallow volcanic conduit during eruption. The desulfidation reaction of Po may be used as a geospeedometer in explosive eruptions.

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The mechanism of water dissolution in silicate melts and glasses is an important factor governing its effects on their physical and thermodynamic properties. Our previous studies have revealed that for Ca-Mg silicate melts (glasses), both SiOH and free OH (e.g. MgOH), whose formations have opposite effects on the network structure and viscosity, are present. Whether free OH also occurs in hydrous alkali silicate systems has been controversial. Here we demonstrate from a combined ¹H MAS NMR and double-resonance (²⁹Si-¹H and ²³Na-¹H) NMR study that water dissolves predominantly as SiOH and molecular H₂O in Na silicate melts (glasses).

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The carbon isotopic fractionation between CO₂-rich fluid and granitic melt was determined to be Δ_f-m = +0.8‰ at 1200 °C and 10 kbar. Infrared spectrometry revealed that both CO₂ molecule and CO₃^2- are present in this melt. The carbon isotope fractionation is modelled as a linear function of the ratio of CO₃^-2 to CO_2molecule.

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X-ray diffraction Rietveld structure refinement and mid- and far-infrared spectral studies have been done on Ga-for-Al and Ge-for-Si substituted synthetic clintonites (Cln), CaMg₂(Al_4-xGa_x)(Si_1-yGe_y)O₁₀(OH,OD)₂ (x = 0.0–4.0, y = 0.0–1.0). In the 720-500 cm^-1 region, Si-O-Al, Al-O-Al, Si-O-Ga, Al-O-Ge, Al-O-Ga, Ge-O-Ga, and Ga-O-Ga deformational bands (tetrahedral-chain bending and “breathing” modes) are observed to overlap strongly. Around 300 and 200 cm^-1 one observes the Ca-O_inner and Ca-O_outer stretching bands, respectively, which show a slight downward frequency shift (~ 7 cm^-1 per Ga apfu) with Ga-for-Al substitution.

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Fe2+/Fe3+ ratio in minerals is an important parameter to investigate occurrences, processes, behaviors of minerals, because the ratio is related oxidation states of minerals.  Mossbauer spectroscopy is an important method to estimate Fe2+/Fe3+ ratio.  Recently, a multi capillary X-ray lens was applied to Mossbauer microspectrometer by Yoshida and Soejima 2010.  In this study, A newly developed Mossbauer microspectrometer for Earth sciences are introduced.  

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We studied a way of separating natural and synthetic rubies on the basis of trace element chemistry. In this presentation, LA-ICP-MS analyzes a synthetic ruby produced by verneuil, czochralski, floating-zone, flux and hydrothermal method and it introduces the summary of the difference of a transition element(Ti, V, Cr, Mn, Fe, Ga etc) or a rare earth element.

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Mineral inclusions  and cathodoluminescence images of gem quality diamonds are studied. Most of gem quality diamonds are P-type, which have been presumably grown in ultramafic magma in the upper mantle.
Contrary to this, many of E-type diamonds, which are commonly seen in pink diamonds, show Mixed-habit-Growth that suggests they have been generated as micro-diamonds in the ultrahigh-pressure metamorphic rocks in the subduction zone, and then they have sunk into deeper to grow further in ultramafic magma.

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We found takanawaite-(Y) from Takanawa Mt. Ehime Prefecture, Japan.

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Kobeite is rare mineral reported in kobe village (old), Kyoto Prefecture. Kobeite is the REE analogue of zirconolite-3T, however study of kobeite is not enough.
In this study, we researched the chemical composition and the crystal stracture of kobeite in well-known localities , Cape Ashizuri ,and Yuge Island.
It is estimated that Kobeite and Zirconolite form the solid solution, and kobeite is the REE analogue of zirconolite-3O.

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Nagatare, Fukuoka is one of the classical mineral localities in Japan. Many mineral species were reported from the Nagatare Li-pegmatite, although systematic mineralogical studies were not made.In this study namibite and hechtsbergite was found in the pegmatie ore of albite, quartz and lepidolite as yellow to brown film.  Chemical conposition and cell parameters of namibite are Cu_0.98Bi_1.92Al_0.04O₂ (V_0.96Si_0.07P_0.02)O₄ (OH), a = 6.216, b = 7.384, c = 7.467, α= 90.19, β = 108.65, γ = 107.36, V = 308.1.Chemical conposition and cell parameters of hechtsbergite are Bi_1.94Al_0.01O(V_1.00Si_0.04)O₄ (OH), a = 6.954, b = 7.539, c = 10.870, β = 106.87, V = 545.4.

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Tourmaline can include variety elements, so the changes of chemical compositions show a chemical development of rocks (Jolliff et al., 1986). A mineralogical study of Li-tourmaline from Japan has not been subjected in detail. Tourmaline from Nagatare Pegmatite, Fukuoka Prefecture, were identified 5 types of and analyzed. Each type had different chemical compositions and a substitution of Al and Li for Fe. Mineral species were composed of elbaite, fluor-elbaite, rossmanite, schorl and fluor-schorl. There was a type enriched with Fe and Mn on rim. A part of body for pink type was replaced with mica, mostly muscovite.

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A granite pegmatite vein cutting dunite occurs at Atagoyama, Koriyama, Fukushima Prefecture, Japan. The recognized U-Th minerals are uraninite, thorogummite, U-bearing pyrochlore-betafite series mineral, sklodowskite, and a masuyite-like mineral.

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The crystal structures of magnesiorowlandite-(Y) [(Y,Ln)₄(Mg,Fe)Si₄O₁₂F₂] and yftisite-(Y) [(Y,Ln)₄(Ti,Al)(SiO₄)₂O[F(OH)]₆] were solved and refined with single crystal XRD data. In magnesiorowlandite-(Y), the Si₂O₇ group, together with (Mg,Fe)O₄F₂ octahedron, connects the 7-coordinate and 8-coordinate REEs polyhedra to form the 3-dimensional structure. In yftisite-(Y), the infinite columns of SiO₄ tetrahedra and (Ti,Al)(O,F)₆ octahedra are linked by the 7-coordinate and 8-coordinate REEs. Yftisite-(Y) can be revalidated as in independent mineral species with these new data, although this mineral has been discredited by the IMA commission in 1987 because of incomplete chemical analysis of the original description.

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The crystal structure of suzukiite from the Mogurazawa mine, Gumma Prefecture, Japan is orthorhombic, space group Cmcm, a = 5.3546(16), b = 15.249(5), c = 7.094(2) Å, Z = 2.  The EPMA analysies gave an empirical formula; (Ba_0.977Sr_0.027)_{S 1.004}V_1.013Si_1.984O₇.  The refinement with single-crystal XRD data set measured on a CCD-diffractometer employing Mo Ka radiation converged into R = 0.0207 for 1508 reflections [I>2s(I)].  The refinement suggested the space group Cmcm for suzukiite.  The b parameter of suzukiite is larger than that of haradaite.  The crystal structure of suzukiite is isomorphous with that of haradaite, and consists of (Ba,Sr)O₁₁-polyhedra, SiO₄-tetrahedra,  VO₅-square pyramid.

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A brackebuschite group mineral occurs as yellow powder with quartz, pyromorphite and mimetite from the dump of the Asaka gypsum mine, Fukushima prefecture, Japan. Electron microprobe analysis gave the empirical formula Pb1.92Fe0.96 [(V0.86P0.70As0.19S0.24)2.01O4] (OH)). It corresponds to a P analogue of calderonite. The powder X-ray diffraction pattern resembles that of calderonite. Lattice parameters obtained with the powder X-ray diffraction method are; a=7.734, b=5.952, c=8.851(Å), β= 111.85deg.

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Makovickyite (Ag_1.5Bi_5.5S₉) and cupromakovickyite (Cu₈Pb₄Ag₂Bi₁₈S₃₆) have been found in the Ohari mine, Tsuruoka City, Yamagata Prefecture, Japan. Makovickyite and cupromakovickyite occur in the chalcopyrite-muscovite-quartz ore. The empirical formula of makovickyite is Ag_1.27Cu_2.60Bi_10.25Pb_0.28S₁₈ (based on ΣS = S+Te+Se = 18). The unit cell parameters from the X-ray single cristal of the mineral are a = 13.246 (2), b = 4.055 (7), c = 14.679 (2) Å, β= 99.469 (2)°, V = 777.77 (3) Å ³ The empirical formula of cupromakovickyite is Ag_2.43Cu_8.66Bi_18.07Pb_2.32S₃₆ (based on ΣS = S+Te+Se = 36).

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Small amounts of ferric iron were detected in olivine from basalt lava of Kuroshima volcano. HRTEM observation and ED data indicate that the ferric iron detected in olivine exist within the olivine structure. In olivine crystals, precipitates occur in the rim and fractures. The precipitates on the rim of olivine are magnetite and silicate mineral, and magnetite shows topotactic relationship with host olivine, suggesting direct crystallization of magnetite from olivine structure. Moreover, a possibility that ferric iron in the olivine exists not only in M2 site but M1 may be suggested by the magnetite which had topotactic relations with olivine.

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Occurrence of ferric iron and precipitates within olivine phenocrysts in andesitic scoria from Kasayama volcano, Hagi, Yamaguchi Prefecture, were investigated to evaluate an effect of high temperature oxidation. Small amounts of ferric iron were detected in olivines from the andesitic red-brownish black scoria was determined using ⁵⁷Fe Mössbauer spectroscopy. Since ferric iron within olivine in this study is not due to any ferric iron-bearing impurity, ferric iron should be located at any site in olivine structure. Olivine phenocrysts in the red scoria contain abundant precipitate minerals including hematite, enstatite and magnesioferrite. Olivines in the red scoria reach 99 mol% Fo.

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Cuprobismutite group minerals (cuprobismutite, hodrushite, kupcikite, paderaite) have been found in the Ohari mine, Yamagata Prefecture, Japan. These minerals have been found with the makovickyite, and are closely intergrowthed them. The empirical formula of cuprobismutite is C Cu_8.12Ag_1.57(Bi, Pb)_12.30S_24.00 hodrushite is (Cu, Fe)_8.35(Bi, Pb)_11.58S_22.06, kupcikite is Cu_3.56Fe_0.54Bi_4.91S_10.0 and paderaite is Cu_7.00(Cu_0.50,Ag_0.17)_0.67Pb_1.27Bi_11.03S_22.00, individualy. The feature of the trace elements (Fe, Ag, Pb) in each mineral, is consistent with Topa et al. (2003).

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In Japan Li-tourmaline has been reported (Uehara et al., 2011, etc.), however, a mineralogical study of Li-tourmaline from Japan has not been subjected in detail. Li-tourmaline from Nagatare, Myokenzan, and Okueyama were analyzed and compared. Black and indigo tourmaline were enriched with Na and Fe. Light blue and pink one from Nagatare, pink and green one from Myokenzan and colorless one from Okueyama were enriched with Al and Li. Tourmaline from Nagatare were composed of elbaite, fluor-elbaite, rossmanite, schorl and fluor-schorl. One from Myokenzan and Okueyama were elbaite, fluro-elbaite, schorl and fluor-schorl. There were Mn-rich fluor-elbaite.

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We discovered allanite subgroup minerals in the tephroite and rhodochrosite that vein minerals from the ferromanganese deposit in the accretionary complex. Allanite subgroup minerals that from the ferromanganese deposit are recognized various characteristic than from pegmatite. It is richer LREE (ex. La or Ce) and V³⁺, Mn²⁺ and poorer HREE (ex. Gd or Dy) and Al, Th, U.

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Allanite means the minerals belongs to epidote group-allanite subgroup, mainly allanite-(Ce) [CaCeAl₂FeSi₃O₁₂(OH)₂]
This study sums up the chemical composition of allanite from Ryoke granitoids, Cape Ashizuri granitoids, and Ohkueyama granitoids.
Allanite from ryoke and Hiroshima granite is allanite-(Ce), and later is rich in Y, MREE, and HREE.
Allanite from Ryoke pegmatite is identified as allanite-(Ce), Uedaite-(Ce), and allanite-(Y).these are subdevided into two type based on REE pattern.
Allanite from Cape Ashizuri granite is poorer in La, MREE, and HREE than one from Cape Ashizuri syenite aand rapakivi granite.
Because of feldspar crystalization, allanite becomes rich in Y,MREE, and HREE.
Allanite from Ohkueyama pegmatite is identified as allanite-(Ce), and poorer in Y, MREE, and HREE than one from Ryoke pegmatite.

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It is known ferromanganese ore compose hematite, magnetite, rhodochrosite and caryopilite. We are found it composes various subconstituent mineral by our study. It is interested to discover a new yield and new mineral that chromferide, mananilvaite, sperrylite, manganochromite, pyrobelonite and iseite.

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We report the Mn2+ analogue of julgoldite which occur from braunite ore in Kamisugai mine, Ohzu city, Ehime prefecture. The ideal formula is Ca₂Mn²⁺Fe³⁺Si₃O₁₀(OH)H₂O, and emprical formula is (Ca_1.93Mn²⁺_0.06Na_0.05)_Σ2.04(Mn²⁺_0.89Mg_0.11)_Σ1.00(Fe³⁺_1.01Mn³⁺_0.70Al_0.25Ti_0.05)_Σ2.01Si_2.99O₁₀(OH)₂H₂O.

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