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Introduction: The spacecraft Hayabusa2 explored C-type asteroid Ryugu and brought back representative samples of Ryugu to the Earth in 2020 [1]. We performed reflectance spectroscopy of Ryugu samples to investigate (1) spectral diversity among Ryugu samples and (2) similarities and differences between Ryugu samples and carbonaceous chondrites. These results can also be applied to spectroscopic observations performed by the spacecraft [2,3]. Sample and Analysis: We measured Visible-infrared (Vis-IR, 0.4-18 μm in wavelength) reflectance spectra of 6 and 8 coarse grains (> 1mm in size) collected from the first and second touchdown sites, respectively, and some carbonaceous chondrites. Samples were put into an air-tight cell sealed with a CaF2 or ZnSe window together with reflectance standards. All the sample handling was performed in a pure-N2 -purged glove-box to avoid atmospheric alteration of the samples. Petrological and mineralogical characterization of the samples including synchrotron X-ray computed tomography and X-ray diffraction analysis was done by other analysis groups in the Hayabusa2 initial analysis "Stone" team [e.g., 4]. IR signature of Ryugu samples compared to hydrated chondrites: All the Ryugu coarse grains have an absorption band at ~2.71 μm attributed to Mg-rich phyllosilicates and a reflectance maximum (Reststrahlen band) at ~9.8 μm suggesting saponite-bearing phyllosilicate composition. These signatures of phyllosilicates of Ryugu are similar to those of CI chondrites, which is consistent with mineralogical observations of Ryugu samples [e.g., 4]. Ryugu sample spectra show absorption features due to aliphatic compounds (3.4 μm), carbonates (e.g., ~3.4, 3.95 μm), and some samples show an absorption feature at 5.8 μm probably due to carbonyl compounds [5]. Ryugu samples show a sharper 2.7 μm band than CIs, suggesting that they contain little molecular water compared to CIs. Sulfate features are not observed in Mid-IR reflectance spectra of Ryugu unlike CIs [e.g., 6]. Tagish Lake C2-ungrouped chondrite also shows an absorption band at ~2.7 μm and Reststrahlen band at ~9.8 μm. However, IR spectral features due to carbonates are more significant in the spectra of Tagish Lake than those of Ryugu as seen in absorption bands around ~3.4 μm and a reflectance maximum at 11.2 μm [7]. CM chondrites also consist mainly of hydrated minerals, however, their spectral shapes around ~3 μm and ~10 μm are different from those of Ryugu most likely due to the different phyllosilicate composition. Vis reflectance spectra of Ryugu samples: Ryugu coarse grains have ~2-4% of reflectance in the v-band (0.55 μm) at the phase angle of 30 °, which is roughly consistent with those of hydrated carbonaceous chondrites (CI, CM, Tagish Lake, and Tarda). The reflectance spectra of CO and CV chondrites, which are dominated by anhydrous minerals and more chondrule-rich, are brighter than those of Ryugu samples. The IR spectra suggest the compositional link between Ryugu and CI chondrites, however, Vis reflectance spectra of Ryugu are not similar to CI chondrites. Low reflectance Vis spectra without a UV drop (a sudden reflectance decrease towards UV wavelengths) of Ryugu samples are not similar to unheated Orgueil but similar to Orgueil samples heated at 300-400 °C for 50 hours (or longer) in reduced conditions [8]. The causes of differences between Vis spectra of Ryugu and unheated CIs may be explained by: (1) atmospheric alteration of CIs (e.g., oxidation and water adsorption of CIs [e.g., 9]), (2) different organic composition, and (3) gentle heating experienced by Ryugu. Vis reflectance spectra of Ryugu particles show some diversity of properties (reflectance, spectral slope, and overall shapes), while IR spectra are consistent among samples. This suggests that the spectral diversity of Ryugu samples are originated from physical properties or orientations of sample surfaces rather than the compositional differences among individual particles. [ABSTRACT FROM AUTHOR]

Introduction: JAXA's Hayabusa2 mission has successfully returned to Earth ~5 g of pebbles and sand from asteroid (162173) Ryugu, a near-Earth carbonaceous asteroid [1]. Preliminary analyses of Ryugu's returned samples revealed they have diverse sizes and contain rugged and smooth particles [2]. Additionally, near-infrared reflectance spectra of Ryugu samples showed the presence of absorption features at ~2.7 µm and ~3.4 µm, attributed to OH- and carbon-bearing materials, including organics and carbonates, respectively [2, 3]. Here, as part of the Hayabusa2 Initial Analysis Stone Team we acquired more spectra of Ryugu samples for further study of the asteroid mineralogy and chemistry. The studied sample (C0002) was retrieved during the mission second touchdown. Ultraviloet (UV), visible and near-infrared (NIR) spectra of the sample were measured in simulated space vacuum conditions. Instrumentation and Procedure: Bidirectional reflectance spectra (incidence=15°, emission=45°, phase angle=60°) of parts of a large Ryugu sample of C0002 (C0002-003 and 004) (< 500 µm in grain size) were collected at the Laboratory for Spectroscopy under Planetary Environmental Conditions (LabSPEC) at the Johns Hopkins University Applied Physics Laboratory (JHU APL). All spectra were collected under space simulated vacuum conditions using a Bruker Vertex 70 FTIR with a spectral range between ~1 µm to 8 µm and spectral resolution of 0.5 cm-1, a McPherson vacuum UV/vis monochromator spectrometer that covers the spectral range between 0.13 µm and 0.57 µm, and a SVC HR-1024i spectrometer with a spectral range between 0.3 µm and 2.4 µm. The spectrometers were mounted to an ultra-high vacuum (UHV) chamber. Because of the very small quantity of the received sample, we had to design and build a new and custom sample holder (~2 mm in diameter) that we filled with Ryugu sample and loaded into the sealed vacuum chamber. Ryugu sample spectra were collected under ambient conditions and periodically as the chamber pumps down and after the sample was left to pump down overnight. Final sample spectra were measured after the chamber reached its base pressure (~10-8 Torr). Because some of our sample was mixed with glycol phthalate glue, we were not able to slightly heat the sample (to drive off the remaining adsorbed terrestrial water) to avoid altering the physical properties of the sample. Results: Here we present our preliminary spectral measurements and analysis of Ryugu sample C0002. Figure 1 shows a UV/Visible spectrum of the sample, measured under space simulated vacuum conditions. The shown UV/Visible spectrum is characterized by a red slope in the ~0.25-0.57 µm spectral range with no apparent and strong absorption features. In this work, the measured UV, Visible, and NIR spectra of Ryugu sample will also be compared to Ryugu samples that were measured by other teams. [ABSTRACT FROM AUTHOR]

Introduction: The mineralogy, petrology and chemical properties of the samples collected from the asteroid 162173 Ryugu by the Hayabusa2 spacecraft show that the samples correspond to CI meteorites not affected by terrestrial weathering (e.g., [1,2]). Our analysis using SR-based X-ray nanotomography (XnCT) is also consistent CI meteorites [3]. Here we report the morphologies of major mineral phases in 3D to discuss their crystallization conditions in aqueous alteration together with their crystallization sequence based on their textures. Methods: We examined 75 particles (10 ~ 180 μm in apparent size) by XnCT at BL47XU of SPring-8 [3]. Most of them were imaged by DET-SIXM method combined with absorption and phase-shift tomography to discriminate mineral phases with the voxel size of 50 ~ 110 nm, their Mg# and densities. Some samples were imaged by absorption tomography with higher resolution (voxel size: 15 ~ 18 nm). Results and Discussion: The matrix of analyzed particles is mainly composed of Mg-rich phyllosilicates (serpentine and saponite, 82 vol.%) with different features (fine to coarse aggregates, Mg# = 0.75 ~ 0.92 (mean: 0.83± 0.04), density = 1.2 ~ 2.1 (mean: 1.7±0.26) g/cm³), IOMs (0.7 vol.%) and voids (12 vol.%). The major minerals in the matrix are magnetite (2.5 vol.%), Fe(-Ni)S (1.4 vol.%; pyrrhotite >> pentlandite), dolomite (1.2 vol.%), breunnerite and apatite (0.2 vol.%). The data here should show the representative feature of Ryugu samples through the 3D analysis of abundant particles without selection bias but may have large uncertainties for the modal abundance in particular IOMs due to insufficient spatial resolution and thresholding of the XnCT analysis. 3D morphologies. Magnetite has a variety of morphology (typically a few ~ 10 μm); spherulite and its aggregate, framboid composed of mono-dispersed grains of a few 100s nm ~ a few μm, plaquette, large equant grains composed of {311} and elongated grains. Transitional morphologies were also observed. Whiskers (~0.5 μm thick and 20 μm long) and cube (~1 μm) are rarely present as well. In contrast, pyrrhotite is mostly separated hexagonal plates ({100} and {001} in the hexagonal setting) with different size (longest length: <1 ~ 60 μm). The width/length ratio ranges from 0.06 to 0.98 (mean: 0.43±0.20) and is independent of the size. Pentlandite (<~5 μm) is embedded in pyrrhotite or present as fragmented grains in the matrix. Nano-sized pyrrhotite and pentlandite grains were also observed in some matrix by TEM [4] although their morphologies were not clearly known. Dolomite is usually present as aggregates of subhedral ~ euhedral grains (<1 ~ 50 μm). Some are euhedral grains of flattened rhombohedron probably composed of {101}. Separated breunnerite grains (30 ~ 100 μm) are thin rhombohedron of possibly {012}. Apatite is usually present as aggregates of subhedral ~ euhedral grains (<1 ~ 50 μm) and one hexagonal prism of {100} (or {110}) and {001} was observed. Crystallization sequence. The crystallization sequence of the major minerals estimated based on inclusions and their relative enclosing relations, which can be easily recognized in 3D, is follows; magnetite → Fe(-Ni)S (pentlandite → pyrrhotite) → apatite → dolomite/breunnerite. For magnetite, the sequence is likely spherulitic → plaquette/framboidal (from fine to coarse) → equant/elongated. This indicates that magnetite crystallization condition changed from high to low supersaturations. The overall sequence can be explained by aqueous alteration of primitive solar materials such as GEMS-like materials. The high supersaturation for magnetite was probably caused by abrupt dissolution of relatively Fe0 or FeO-rich amorphous silicates followed by precipitation of magnetite and Mg-rich phyllosilicates. In contrast, pyrrhotite hexagonal plates with different size might be formed by dissolution and reprecipitation from original Fe(-Ni)S nanograins at relatively low supersaturation. Dolomite and apatite having equilibrium shapes [5,6] indicate that they precipitated at relatively low supersaturations in the late stage. [ABSTRACT FROM AUTHOR]

Introduction: Asa part of the Hayabusa2 initial analysis [1], we analyzed eighteen Ryugu "stone" samples of 1 ~ 8 mm in size: seven stones from the 1st touch down site and eleven from the 2nd touch down site. Ryugu stones were analyzed first using X-rays. UV, visible, near-infrared mid-infrared, and mutes probes for surface reflectance spectra, internal 3D structure and element distribution [2], crystal structures, and bulk composition of light elements such as C, N, and 0. Measurements for magnetic, thermal, and physical properties mine some stones were also performed. TOF-SDIS analysis of fluid inclusions is being continued [3]. Small particles separated from some stones were ana-lyzed by IR-CT [4]. Based on 3D-CT images of individual stones, objects of interests were identified, separated by pFIE cutting, and exposed by polishing on the surface of epoxy disks. FE.EPMAJFE-SEM analysis was made on ~40 polished epoxy disks for chemical composition and textural observation [5-9]. FIB sections and small (~15 μ in diameter) fragments were separated from the polished surface and analyzed by rod, S170.1, XRF, and nano-CT. Results and discussion: Eighteen stone 2D and 3D images indicate that Ryon samples are breccias of small fragments (< ~1mm in size) of basically CI chondrite mineralogy [10]. Most of the fragments are heavily altered and consists mainly of phyllosilicates. carbonates (dolomite and brannerite), Fe sulfides and oxides, and phosphates (F-bearing hydroxyapatite); this mineralogy we call the major lithology. The mineralogy of the fragments of the major lithology shows some diversity. the abundance and shape of carbonates and phosphates differ among fragments. On the other band, some fragments in many stones are less altered and contain anhydrous silicates such as olivine and low-Ca pyroxene of typically Mr#>97 but down to Mg#~50, which we call the less-altered litbology. In the less-altered lithology, the abundance of olivine and pyroxene differs between fragments and some fragments contain them up to - 10 volti. Therefore, fragments with the less-altered lithology can be classified as CL-type thou-drite material. Most, but not all. fragments with the less-altered lithology contain only calcite as carbonate, phosphides (FeNi)3P and (Fe, Ni)2P instead of apatite. and poorly-crystallized amorphous silicates. Small (<20μm in size) type-I barred and porphyritic chondrules and CAI with spinel+hibonite-tennskite assemblages also occur. GaIS-ble ob-jects are abundant in the least-altered fragments. In summary, mineralogical and physical properties of Ryugu samples reveal incipient to advanced aqueous alteration in its parent asteroid. [ABSTRACT FROM AUTHOR]

Introduction: Initial analysis of asteroid Ryugu samples has revealed that they were mm-μm scale breccia mostly composed of aqueously altered phases (e.g., Mg-Fe phyllosilicates, carbonates) and showed remarkable similarities to CI chondrites in mineralogy and chemistry [e.g., 1,2]. Our detailed analysis of Ryugu samples has detected small amounts (<<1 vol.%) of unaltered silicates that would escape severe aqueous alteration [3]. Olivine is the most abundant (>90 vol%) phase among such unaltered silicates. Although most Ryugu olivine grains are smaller than 5 μm, they bear important information about the precursors of the parent Ryugu asteroid. In this abstract we report additional results of olivine mineralogical study of Ryugu samples, and especially compare with olivine grains in CI chondrites (Ivuna and Orgueil) to further discuss their relationship and possible common origin. Samples and Methods: Polished sections of A0026, A0055, A0063, A0106, C0002, C0023, C0025, C0033, C0040, C0046, C0055, C0076 and C0103 were analyzed using JEOL JXA-8530F FE-EPMA at Univ. of Tokyo. The quantitative analysis was performed at 12 kV accelerating voltage / 30 nA beam current (counting times at peaks: 30 sec), allowing us to obtain accurate compositions even from ~1 μm olivine grain. For comparison, polished sections of Ivuna and Orgueil with similar size to Ryugu samples (a few mm in size) were analyzed by the same method. Results: Olivine grains are present only in weakly-altered lithologies in Ryugu samples [e.g., 2]. So far we have not found olivine from Chamber A samples. Although we acquired compositions from ~200 additional olivine grains this time, the obtained compositions are basically identical to what we have already obtained [3]. Olivine compositions are clustered at Fo99 and extends to Fo44. Most olivine has 0.0-0.7 wt% MnO, and rare (<5%) LIME olivine (MnO/FeO>1 in wt%) grains are present. There is a positive correlation between Mn and Cr in olivine (MnO: 0.0-1.5 wt% vs. Cr2O3: 0.0-0.7 wt%) (Fig. 1). Most olivine grains are Ca-poor (CaO: <0.1 wt%). The comparative analysis of Ivuna and Orgueil has shown that both samples are similarly brecciated to Ryugu samples in size and mineralogy, and we found that weakly-altered lithologies contain tiny (mostly <5 μm) olivine grains. The size, texture, abundance and mineral compositions of olivine in Ivuna and Orgueil are strikingly similar to those of Ryugu olivines both in major and minor elemental compositions (Fig. 1). Discussion and Conclusion: We found identical olivine mineralogy between Ryugu samples and CI chondrites, further supporting that Ryugu samples are similar to CI chondrites [e.g., 1,2]. Although olivine has been reported in CI chondrites, the reported size is larger than 50 μm in many cases [e.g., 4]. Smaller olivine grains (<5 μm) as found in this study have not been well documented except few cases [e.g., 5]. Because the reported CI olivine composition is slightly different from our CI chondrite data [e.g., 4], there would be multiple origins for olivine in CI chondrites and Ryugu samples. In any case, the presence of small olivine grains (<5 μm) found in Ryugu and CI chondrites is important because such tiny olivine could be common precursors of these chondritic materials. [ABSTRACT FROM AUTHOR]

Introduction: The successful probing, return and curation of asteroid Ryugu provides pristine sample material from the surface and subsurface of this C-type asteroid. The sampled material of the Hayabusa2 mission includes many coarse-grained fragments [1, 2]. In order to obtain the highest level of scientific output the initial study included several non-invasive and non-destructive analytical techniques. Synchrotron X-ray fluorescence computed tomography (SXRF-CT) [e.g. 3] is an ideal non-invasive analytical technique to achieve detailed in depth structural and chemical information and was applied to several mm-sized rock fragments of the asteroid Ryugu from both, surface and sub-surface samples. Here we present the first dataset on coarse grain C0033, collected at the second touchdown site. Methods: X-ray fluorescence spectroscopy experiments were performed at the P06 beamline of PETRA III (DESY, Hamburg, Germany) and at the ID15A beamline of the ESRF (Grenoble, France). The excitation energy E0 was 20.5 keV and 90 keV respectively, using Si(111) monochromator optics. The Kirkpatrick-Baez (KB) mirrorbased X-ray beam focusing provided a 0.2×0.24 µm² beam spot size at sample position during the P06 experiments, and a 0.5×0.5 µm² beam spot at sample position for the ID15A experiments. High-Energy SXRF: Every detailed SXRF analysis was started with a chemical 2D overview projection of the full volume of the mm-sized rock fragment. In case of sample C0033 an Fe-rich vein was identified. Several crosssection CT scans were performed during our subsequent study, one exactly at the height where the Fe-rich vein was observed. The cross section indicates the presence of REE-rich phases throughout the vein and confirms the vein-like nature of the Fe-enriched area. Lower-Energy SXRF: For further studies a polished section (~100 µm thick) of grain C0033 was prepared exactly at the height of the magnetite vein and was then further analysed at lower X-ray energy (20.5 keV) at PETRA III beamline P06. The Fe distribution found confirms the existence of a magnetite-rich vein. Ca and Y element maps indicate the presence of multiple apatite grains closely related to the vein. Quantification: The SXRF measurements not only provide element distribution maps but can also be quantified. In order to get better statistics small area maps and point analyses were performed. The resulting CI normalized trace element concentrations of magnetite and apatite grains located within the magnetite vein observed in C0033 show values close to CI bulk composition. All quantified measurements were acquired at PETRA III P06 beamline applying a primary beam energy of 20.5 keV. Discussion and Conclusion: The detailed SXRF study of mm-sized Ryugu rock fragments enabled the identification and localization of unique sample characteristics like the magnetite-apatite vein found in grain C0033. Veins crosscutting the sample material are compelling evidence for intense hydrous alteration on the parent body. The widespread occurrence of sulphate veins found in most CI chondrites was first interpreted as evidence for late stage lowtemperature alteration on the asteroid [e.g. 5], but later clear proof was found for the terrestrial formation of these features in almost all samples [6]. The study of rock samples sampled on the sub-surface of asteroid Ryugu now for the first time enables to study hydrous alteration processes without any terrestrial alteration. Our study shows compelling evidence for the existence of low temperature hydrous alteration veins on asteroid Ryugu. Surprisingly, the vein consists of a mixture of mostly magnetite with apatite, which is in contrast to the observation of carbonate veins found on the surface of asteroid Bennu [7]. [ABSTRACT FROM AUTHOR]

Introduction: In December 2020, the Hayabusa2 reentry capsule returned 5.4 g of material from the asteroid Ryugu. A fraction of the collected material was then examined by Initial Analysis Teams. As a part of the Mineralogy / Petrology STONE team, we received ~30 small fragments to study the 3D heterogeneity and the assembly of the different phases. Material and methods: In this study, we will present the results of a muti-analytical sequence applied to nine micrometric Ryugu fragments (ranging from 30 to 80 µm in size), coming from 3 bigger millimetric grains (A0064, C0046, and C0002). These fragments were welded with platinum on metallic needles using FIB (Focus Ion Beam) microscopes in Saclay and Lille [1]. Then, we analyzed these fragments using an IR micro-tomography setup available at the SMIS beamline of the SOLEIL synchrotron (France). Multiple configurations were used: analyses in transmission by Infrared Computed Tomography [2] (IR-CT) and analyses in reflectance by Infrared Surface Imaging [3] (IRSI). Regions of interest with peculiar spectral signatures were identified on the 3D volume and 3-µm thin-slices (~ 15 x 20 x 3 µm³) around these regions were extracted using FIB. They were finally analyzed in 2D with high-resolution IR imaging and SEM-EDX. Average composition: We will present the average IR spectra in the 2.5 - 12.5 µm range both in reflectance and transmission of the 9 small studied fragments. Several grains showed IR signatures at ~ 2.7 µm, 3.0-3.1 µm, 3.4 µm, and 3.9 µm, in a good agreement with the bands identified by NIRS3 or by MicrOmega in the JAXA curation facility [4,5], plus several mid-IR signatures of great interest, such as bands attributed to Si-O stretching in phyllosilicates, and C=O stretching in organics and carbonates. In general, the 2.7 µm feature observed in our data exhibits similar maximum position but is deeper to the one observed with NIRS3. However, we notice a variability of the composition between the 9 fragments, for instance in the intensity of the 2.7 and 3.4 µm features. Study of heterogeneity: The small fragment C0002-FO019, exhibits two regions with very different IR signatures. The difference in the position and the shape of the SiO feature could sign different lithologies affected by various degrees of aqueous alteration. In particular, some spectra show a shoulder at ~ 998 cm-1 which could be due to anhydrous silicate related to a less-altered lithology [6]. The origin of the variation of the 10 µm band (chemical composition, or structural diversity of the mineral) will be discussed. A correlation with the 2.7 µm band will also be presented. Complementary measurements performed with SEM-EDX to better constrain the mineralogy of the surface of the extracted thin-slices will be presented and we will discuss the structural diversity at the scale of ~100 nm. [ABSTRACT FROM AUTHOR]

Introduction: Micrometeorites have preserved pristine material that shed light on primitive conditions of the Solar System. They constitute the dominant extraterrestrial material accreted by the Earth nowadays, and are most efficiently collected in Antarctica (Antarctic micrometeorites - AMMs [1, 2]). Mineralogical composition of micrometeorites allows to retrace their primitive formation conditions and degree of alteration. Primitive carbonaceous (Cb-type) asteroid Ryugu samples were returned by the Japanese mission Hayabusa2 in December 2020. Both surface (Chamber A) and potential sub-surface (Chamber C) of Ryugu were sampled [3]. The textures and mineralogical compositions of AMMs and Ryugu samples are studied to investigate a potential link between these objects. Materials and Methods: Twelve sample from Ryugu were prepared and analyzed by analytical scanning electron microscopy (SEM-EDX), electron probe microanalysis (EPMA), or Fourier-transform IR microscopy (µ-FTIR) and far-infrared microscopy (FIR). Among these twelve samples, 5 originate from chamber A (A0064-FO013-17, A0064-FO0020, A0106-13, A0108-15, A0108-19) and 7 were extracted from chamber C samples (C0002-FC016, C0002-FC017, C0040-FC025, C0046-FO004-010, C0057-5, C109-04, C109-10). For SEM & EPMA analysis, they were moved with a quartz needle from their quartz holder to a carbon tape disk and were carbon-coated on 4 stubs. After SEM examination, these stubs were embedded in epoxy and polished with diamond pads down to 0.25 µm. The AMMs selected for this study were collected in Antarctica from melted ice (Cap Prud'homme) and snow (Concordia collection). AMMs showing magnetite framboids and platelets in a phyllosilicate matrix ("C1-like AMMs") were selected to be compared with Ryugu samples. Polished sections of Ryugu and AMMs samples were analyzed by EPMA at 15 kV and 10 nA at CAMPARIS University Paris Sorbonne (Jussieu). For µ-FTIR/FIR analyses, the Ryugu samples and 4 AMMs samples (DC16-14-315, DC16-11-429, DC16-11-430, DC16-11-436) were flattened in custom-made diamond cells and were analyzed on the SMIS line at synchrotron SOLEIL (France) in July, October 2021 and April 2022. The synchrotron beam was coupled to a Nicolet continuum IR microscope. Hyperspectral maps with a beam aperture of 6 x 6 μm, and 3 μm step have been produced, and IR nanospectroscopy (AFM-IR) was also performed on some samples ([4, 5]). Furthermore, 5 AMM FIBsections were analysed by synchrotron-based STXM-XANES at the C, N and Fe K-edges in September 2021 and February 2022. Results and discussion: SEM analyses showed that Ryugu samples are composed of a fine-grained hydrated matrix containing characteristic aggregates of magnetite framboids, platelets and "sprays", from 200 nm to 1 μm. EPMA analysis of chamber A and chamber C Ryugu samples revealed a dominant phyllosilicate matrix, mostly saponite and Mg-serpentine, with magnetite, carbonates (mostly dolomite), Fe-Ni sulfides such as pyrrhotite or pentlandite, and rare phases such as apatite and a potential Mgphosphate. The infrared (IR) analyses of Ryugu samples revealed widespread organics intimately linked to phyllosilicate matrix and the presence of carbonates and IR-opaque minerals in the matrix [4]. According to EPMA and µ-FTIR analysis of Ryugu samples, less and smaller carbonates are observed in chamber C than in chamber A samples. Magnetite framboids and platelets, in that proportion, are typical of C1 meteorites (especially CI1 and CR1), and these characteristic features are also found in ~5% of the AMMs from the Cap Prud'homme and Concordia collections, that we quote as "C1-like AMMs". Ryugu samples seem to be enriched in Ca and Mn, as measured by averaging the EPMA measurements, compared to C1-like AMMs, which are comparatively enriched in Al and K. The IR and STXM-XANES analyses of AMMs are being processed, but already confirmed the presence of phyllosilicates (although with a rare structural OH signature, as also seen in other types of hydrated AMMs [8, 9]), carbonates and ferric (Fe3+) iron within the matrix of AMMs. Conclusion: The mineralogical components of Ryugu samples show similarities with C1 meteorites, except for the presence of sulfates and the lack of Fe sulfides in C1 meteorites, probably due to the terrestrial alteration of sulfides in C1 meteorites [7]. Around 5% of the Cap Prudhomme and Concordia AMMs show magnetite framboids or platelets ("C1-like AMMs") that show similarities with Ryugu samples. The comparison of C1-like AMMs with Ryugu samples is ongoing. Acknowledgments: This work was supported by CNES (MIAMI-HY2), the French ANR (COMETOR, ANR-18-CE31-0011) as well as INSU (PNP, PCMI), IN2P3, DIM-ACAV+ (Région Île de France), CNRS. We are grateful to the French and Italian polar institutes IPEV and PNRA, for their financial and logistic support to the micrometeorites collection at the vicinity of the CONCORDIA station (Dome C). [ABSTRACT FROM AUTHOR]