Marco Baroni

Understanding how the glass/crystal ratio influences the spectral response of volcanic rocks is crucial for interpreting planetary remote sensing data. Here, four mafic rocks simulating a possible Martian composition were synthesized with identical bulk chemistry but different mineralogical assemblages, from fully amorphous to ∼70 wt.% crystal content, to investigate how crystal content affects Visible and Near‐Infrared (VNIR) reflectance spectra. Bi‐directional VNIR reflectance was collected at room temperature across a range of incidence (0°, 30°, 60°) and emergence (−70° to +70°) angles. The diagnostic absorptions of the two most abundant phases, pyroxene and glass, are not distinguishable in the spectra and can even reproduce the spectral fingerprint of olivine, absent from the samples; only minor iron oxides (magnetite and hematite, ∼1–7 wt.%) produce clearly identifiable absorptions. Instead, spectral slope emerges as the primary proxy for the glass/crystal ratio: NIR/VNIR slope decreases systematically with increasing crystal content, driven jointly by the incorporation of iron oxides and the loss of the positive‐slope contribution of residual glass. Principal Component Analysis and k‐means clustering independently confirm this control, identifying three clusters that map onto the glass/crystal ratio. This decoupling indicates that the crystal content of a mafic terrain cannot be inferred from pyroxene‐ or glass‐related absorptions alone, but rather from spectral slope and iron‐oxide features. These results experimentally support previous hypotheses linking the spectral diversity of Martian mafic terrains to their degree of crystal content and oxidation state and highlight variable glass abundance as an under‐considered contributor to the spectral interpretation of the Martian surface.

The Makgadikgadi Salt Pans (MSPs) in northern Botswana offer to study the mineralogy of evaporates and clays derived from fluvio-lacustrine sediments in their geological context. A field campaign taking place in August 2022, funded by Europlanet 2024 RI (grant agreement No 871149) was performed to investigate variations in the mineralogical composition of the pan materials with respect to neighboring and/or underlying (bedrock) units. Spectral measurements were performed directly in the field with a portable spectroradiometer (PSR) that samples the surface in the visible and near-infrared (VNIR) wavelength range between 0.35 and 2.5µm. In addition to VNIR spectroscopy, samples collected in the field were analyzed in the laboratory using laser-induced breakdown spectroscopy (LIBS) and Raman spectroscopy, a triple combination, which has proven to significantly enhance the scientific potential for studying the mineralogy of planetary analog materials (Stephan et al., 2025). Even more, VNIR spectra acquired in the field provide spectral endmembers, which are now used to classify the currently available data of the MSPs provided by the Environmental Mapping and Analysis Program (EnMAP) of the German hyperspectral satellite mission. EnMAP data cover the same wavelength range in the VNIR as the field instrument and covered major portions of the pans at the same seasonal period of the year.The acquired spectral data reveal that salts dominate a more or less fresh, white to light brown, several mm-thick uppermost crust throughout the pans. They are particularly prominent where the salts themselves or at least the clays underneath this layer are still wet from the rainy season. The special shape of the water-related feature at 2 µm implies that sodium hydrogen carbonates such as trona dominate the salt layer. Although halite should be also present, its spectral signature might be masked by the signature of trona. In the wettest location, a thin greenish layer of organic material has been found, which causes a characteristic feature near 0.7 µm. In regions that have been dry for a prolonged period, clays such as montmorillonite dominate over salts. Bed rocks that are in direct contact with the pan deposits often show a distinct greenish color. Spectra of these rocks are dominated by glauconite (sometimes in combination with illite), which are known to develop as a consequence of slow sedimentation in a marine environment associated with low-oxygen conditions.Intriguingly, lacustrine glauconitic clays could also be confirmed to exist in an ancient lake on Mars (Losa-Adams et al., 2021). Therefore, the collected spectra in combination with the knowledge of their geologic context will be extremely useful for identifying similar environments on Mars by spectrometers working in the visible-near infrared (VNIR) wavelength range (Mars Express OMEGA, MRO CRISM) and providing key parameters for characterizing aqueous Martian palaeoenvironments. References:Stephan et al. (2025). Multi-spectral field study of planetary analog material in extreme environments—alteration products of volcanic deposits of Vulcano/Italy. Earth and Space Science, 12, e2024EA004036. https://doi.org/10.1029/2024EA004036.Losa-Adams et al. Long-lasting habitable periods in Gale crater constrained by glauconitic clays. Nat Astron 5, 936–942 (2021). https://doi.org/10.1038/s41550-021-01397-x.

The physical behaviour of silicate magmas and their eruptive style are strongly controlled by melt structure, volatile content, and cooling conditions, reflected in spectral properties. Magma rheology and eruptive style are primarily controlled by volatile-driven modifications of melt structure (especially due to H₂O), which govern fragmentation during magma–water interactions, producing fine, lithic-rich tephra. Spectroscopic techniques provide a powerful means to investigate melt structure and pre-eruptive volatile contents, offering insights into eruption dynamics.We analysed tephra samples from two phreatomagmatic successions on Vulcano Island (Aeolian Arc, Italy), a natural laboratory to investigate relationships among magma composition, volatile content, and eruption style (Keller, 1980; De Astis et al., 1997). Eleven ash-rich layers were sampled. Field measurements included VNIR reflectance spectra acquired with an ASD FieldSpec spectroradiometer and portable Raman spectroscopy. Diffuse reflectance FTIR spectra were collected using a Bruker Invenio X spectrometer on natural and oven-dried samples (105 °C, 48 h) to evaluate adsorbed water. Quantitative spectral parameters were extracted, including band center, full width at half maximum, and area under the curve in the 300–25000 nm domain. We investigate whether VNIR reflectance spectroscopy and laboratory FTIR measurements can identify spectral criteria diagnostic of eruption style in surge-dominated pyroclastic deposits. Preliminary analyses reveal systematic spectral variations related to volatile content and silicate melt structure. The spectra display absorption features attributed to Fe³⁺, molecular H₂O, OH⁻, Al–OH, and Fe–OH vibrations, enabling extraction of band parameters sensitive to hydration state and polymerization degree. Thermal treatment experiments show reduced band areas and spectral slope associated with H₂O and OH⁻ absorptions after heating, indicating that most water in natural samples is weakly bound or adsorbed. However, water loss varies among stratigraphic levels, reflecting differences in glass content, porosity, and hydration history. Variations in Si–O and Al–O band positions and widths indicate differences in silicate network polymerization, with narrower bands and shifts toward higher wavenumbers consistent with evolved compositions. Overall, the spectral signatures are consistent with highly explosive eruptions involving water-rich, evolved magmas and record internal heterogeneity within the eruptive column, marked by progressive degassing during the eruptive event.This study contributes to the development of spectral reference datasets of terrestrial volcanic materials, essential for interpreting remote sensing data. By linking spectral features to the physical and chemical characteristics of volcanic deposits and their eruptive context, we constrain the nature of volcanic activity on other planetary bodies.De Astis, G.F. et al., 1997. Volcanological and petrological evolution of the Vulcano Is land Aeolian arc, southern Tyrrhenian Sea. J. Geophys. Res. 102, 8021–8050.Keller, J., The island of Vulcano, Rend. Soc. Ital. Mineral. Petrogr., 36, 369–414, 198

Magmatism and volcanism are key processes that shaped the surface of rocky planets in the Solar System, and understanding how magmatism occurred on these planets is essential to reconstruct their geological histories. It is very likely that volcanic terrains on planetary surfaces are covered by products that have a porphyric, aphanitic or hyalocrystalline texture, in which crystalline phases represent only a fraction of the rocks that are mainly composed by amorphous materials such as glasses.Remote investigation of planetary surfaces combines geomorphological analysis with spectral data. Regarding the latter, the interpretation of spectral information from planetary terrains needs to be based on the comparison with reference material.Up to now, libraries and repositories are mostly report information about so-called planetary analogues consisting of crystalline materials rather than amorphous products. This happens because of the lack of spectral features of amorphous products. However, a the presence of amorphous material together with crystalline phases deeply influence the spectral response of the latter [1].For this reason, the Petro-Volcanology Research Group at the University of Perugia started to build up a spectral database of volcanic rocks, both natural and synthetic, to understand how and how much are crystalline and amorphous products influencing each other in determining the spectral response of a rock/terrain. In this work we report the spectral characterization of various products within two ranges: Visible and Near Infrared (VNIR) and Mid-Infrared (MIR).The accounted products consist of:- Synthetic silicate glasses with wide range of chemical composition [2,3]- Synthetic planetary analogues consisting of rocky materials containing both amorphous and crystalline products [4]- Natural volcanic rocksThe overall analysis of the spectral response shows that, within the MIR, it is relatively easy to link the wavelength position of well-known spectral features (Christiansen feature, Reststrahlen Bands, Transparency features) to the silica content of the product itself, no matter which crystalline phases are present within the rock. This finding is of pivotal importance since the determination of silica content is fundamental for a characterization of volcanic products.On the other hand, investigations and analyses on VNIR spectra show that the interpretation within such is more complicated. Indeed, a small presence of Iron-bearing crystals can deeply influence the VNIR spectrum. However, some constrains can be build using empirical parameters and machine-learning approaches.All the spectra produced and published by our research group is or will be made available to everyone, open-source, within the platform hosted by ASI-SSDC (www.ssdc.asi.it/rockspectra/), making it possible for scientist from all-over the world to integrate such data in other researches or to directly compare planetary spectra to laboratory data [4].[1] Horgan, B. H., Cloutis, E. A., Mann, P., & Bell III, J. F. (2014). Near-infrared spectra of ferrous mineral mixtures and methods for their identification in planetary surface spectra. Icarus, 234, 132-154.[2] Pisello, A., Ferrari, M., De Angelis, S., Vetere, F. P., Porreca, M., Stefani, S., & Perugini, D. (2022). Reflectance of silicate glasses in the mid-infrared region (MIR): Implications for planetary research. Icarus, 388, 115222.[3] Pisello, A., De Angelis, S., Ferrari, M., Porreca, M., Vetere, F. P., Behrens, H., ... & Perugini, D. (2022). Visible and near-InfraRed (VNIR) reflectance of silicate glasses: Characterization of a featureless spectrum and implications for planetary geology. Icarus, 374, 114801.[4] Pisello, A., Zinzi, A., Bisolfati, M., Porreca, M., & Perugini, D. (2022). A new spectral database for silicate glasses: a fundamental resource to interpret characteristics of volcanic terrains on planetary bodies (No. EPSC2022-539). Copernicus Meetings.

Introduction: Volcanic and magmatic processes shaped the surfaces and contributed to the mineral diversity of Mercury. Beyond the ubiquitous presence of effusive products (smooth plains) explosive volcanism is suggested by the presence of depressions surrounded by high-reflectance halos, interpreted as eruptive centers, as well as calderas and vents linked to impact structures or faults [1]. BepiColombo hosts SIMBIO-SYS and MERTIS, two instruments that will characterize the surface of Mercury with different methodologies:SIMBIO-SYS (Spectrometer and Imagers for MPO BepiColombo Integrated Observatory System) is a system for imaging and spectroscopic analysis. Its goals are to study surface geology, volcanism, tectonics, age, composition, and geophysics. One of the systems of SIMBIO-SYS is the Visible Infrared Hyperspectral Imager Channel (VIHI), which performs hyperspectral imaging to map the planet's mineralogical composition in the Visible and Near Infrared (VNIR) range [2].MERTIS (MErcury Radiometer and Thermal Infrared Spectrometer) aims to provide detailed mineralogical information about Mercury’s surface by globally mapping spectral emittance with high spectral resolution. Operating in the 7-14 µm wavelength range with high spectral resolution, MERTIS can detect key surface features like the Christiansen feature (CF), Reststrahlen bands (RB), and Transparency features (TF) [3].The interpretation of spectral data from these instruments needs to be based on the spectral response of the reference material. This is complicated by factors such as mineral composition, elemental abundance, temperature, surface roughness, and particle size, which all contribute to spectral response. This study aims to explore the VNIR and MIR spectral response with the goal of building a comprehensive database of Mercury-like silicate glasses to support future spectral interpretations of Mercury's surface, where volcaniclastic materials are thought to be abundant. NVP NVP_Na NVP_Mg SiO2 58.09 55.89 53.85 TiO2 0.98 0.90 0.90 Al2O3 15.54 15.11 12.44 FeO 2.93 3.36 3.34 MgO 16.82 13.80 22.76 CaO 5.04 4.36 6.35 Na2O 0.30 6.35 0.16 K2O 0.32 0.22 0.19 Table 1: The compositions of three starting materials prepared for this study, taken from [4].Methods:Material preparation: Three compositions resembling that of the Northern Volcanic Plains (NVP) on Mercury were chosen: an iron-poor potassium-rich composition resembling the composition of NVP [4] the same one with an addition of Na (NVP_Na), and another with an addition of Mg (NVP_Mg) (Table 1). From these compositions, glasses were reproduced following the procedure illustrated in [6]. Glasses were ground and sieved into grain size fractions: 0–25 µm, 25–38 µm, 38–63 µm, 63–106 µm, 106–150 µm. From these, also Gaussian-like distributions of powders were produced, characterized by mean values of 30, 80, and 120 µm, and standard deviations of 20 and 40 µm.Spectral Analyses: Spectroscopic analysis was performed using a FT-IR apparatus consists of a Bruker Invenio-X spectrometer coupled with Harrick Praying Mantis™ for Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). Samples were measured in atmosphere and corrected to a background measured with a mirror. To focus on SIMBIO-SYS and MERTIS spectral range, we present the spectra in the wavelength ranges 0.4-2µm and 7 to 14 µm.Results and perspectives:VNIR: the spectral shape of all samples is characterized by a generally positive slope and a prominent absorption at ca 1.1 µm, and a second, very weak, absorption at ca. 1.9 µm. These features are the usual ones observed for silicate glasses [5] and are linked to the presence of Fe-O bonds, which are not detectable in iron-free samples.MIR: shape of spectra in this spectral range is influenced by both chemical and granulometric characteristics. First, it is linked to the connectivity rate of the silicate structure consisting of tetrahedral units T, primarily Si, Al, and Ti, namely by the amount of bridging oxygens (BO). Moreover, the vibrations in T-O bonds occur at different wavelengths depending on the number of BO between two Si-tetrahedra (BO) and therefore on the amount of Si, Al and Ti present in the structure [6]. In our set of spectra, local maxima at 10 µm detectable for all spectra can be correlated to T-O bonds and can be assigned to RB feature. All spectra show a local negative peak at ∼8 μm that can be recognized as the CF, a local minimum which appears on both amorphous and crystalline materials, and that is often used as a diagnostic feature for igneous products. Moreover, the presence of fine material produces the presence of TF at ca. 12 μm, occurring when a large surface/volume ratio determines a larger ratio of scattered/absorbed light. Only the spectra related to the finest products show such a feature, reasonably, in our set of spectra.All these spectra will be made available on the SSDC-ASI portal of the PVRG group [7, https://www.ssdc.asi.it/rockspectra/], and the use of these spectra as reference material will be pivotal for the interpretation with data acquired by the instrument onboard the BepiColombo mission such as SIMBIO-SYS and MERTIS. Ongoing parametrization and analyses on these data will also provide models for the identification of putatively unknown igneous materials on Mercury.References:[1] https://doi.org/10.1002/jgre.20075[2] https://doi.org/10.1007/s11214-020-00704-8[3] https://doi.org/10.1007/s11214-020-00732-4[4] https://doi.org/10.1002/2015JE004792[5] https://doi.org/10.1016/j.icarus.2021.114801[6] https://doi.org/10.1016/j.icarus.2022.115222[7] https://doi.org/10.5194/epsc2022-539Additional Information: We acknowledge ASI-UniPG agreement 2019-2-HH.0. Part of this work was supported by the Ministero dell’Istruzione dell’Università e della Ricerca (MUR) through the...

Remotely sensed hyperspectral data provide essential information on the composition of rocks on planetary surfaces. On Mars, these data types are provided by the CRISM instrument (Compact Reconnaissance Imaging Spectrometer for Mars) [1], a hyperspectral camera that operated onboard the MRO (Mars Reconnaissance Orbiter) probe that collected more than 10 Tb of data. CRISM covers a spectral range going from ca. 400 to ca. 4000 nm, with a spectral resolution of 6.55 nm/channel and a spatial resolution of up to 18.4 m/px. The most advanced CRISM data products are the MTRDRs (Map-Projected Target Reduced Data Records) [2]. These data are re-projected onto the Martian surface and are cleaned from the so-called ”bad bands” (noisy stripes).The two main CRISM MTRDR subproducts are the hyperspectral datacube and the spectral parameter datacube. The first contains the detected reflectance spectra, while the second is composed of 60 different spectral parameters, as defined in [3], usually to produce RGB maps emphasizing specific minerals within the scene. Usually, the creation of the RGB maps and the spectral analysis are conducted using commercial software like ENVI©, which are usually not specifically meant for these dataset, inherently implies some costs for the user, and does not always meet some of the fundamentals principles of Open Science [4].Here we present a free open-source tool completely written in Python called pyFRESCO (Flexible RGB Extraction and Spectra Comparison for Observations), which allows the use of CRISM MTRDR data. The software can create RGB maps and select Regions Of Interest (ROI) from which the user can extract and further analyze the spectral data available from the chosen CRISM scene.The possible types of analysis that pyFRESCO supports range from simple descriptive statistics (to obtain, for example, mean spectra of a ROI), and spectra-related pre-processing methods like continuum removal and/or smoothing, to analysis through more complex techniques. One of those techniques being a direct spectral comparison tool that, given a guess taken from the minerals that are present in the MICA files [5], infer the nearest absorption features to the tabulated ones. Another technique, applicable only to mafic minerals, is the calculation of band parameters given in [6] for mafic mineral discrimination (e.g. between pyroxenes and silicate glasses). The last one involves a machine learning driven Modified Gaussian Model [7] for spectral unmixing with either skewed or non-skewed normal distributions.Moreover, with pyFRESCO it is possible to georeference the RGB maps to export them to ArcGIS©/QGIS software.In support of the effectiveness of pyFRESCO, we present a case study conducted on the CRISM target FRT00009B5A that covers the northern portion of Kai crater, located in Meridiani Planum. The choice of this particular case study is motivated by the morphological and compositional complexity shown by this specific target [8], demonstrating that pyFRESCO can be useful especially in complex scenarios that require a detailed analysis of the geological context, evolution, and processes. Bibliography:[1] Murchie, S. 2007. doi:10.1029/2006JE002682.[2] Seelos, F.P. 2016. URL: https://api.semanticscholar.org/CorpusID:217998642[3] Viviano-Beck, C.E. 2014. doi:10.1002/2014JE004627.[4] Barker, M. 2022. doi:10.1038/s41597-022-01710-x.[5] Viviano-Beck, C. E., 2015. URL: https://crismtypespectra.rsl.wustl.edu/.[6] Horgan, B.H. 2014. doi:https://doi.org/10.1016/j.icarus.2014.02.031.[7] Sunshine, J.M. 1990. URL: https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/JB095iB05p06955[8] Baschetti, B. 2025. doi: https://doi.org/10.1029/2024JE008564

Introduction. Several lines of evidence support the idea that Mars once had surface conditions very different from today’s cold, extremely dry environment. In particular, both the planet's morphology and mineralogy indicate that water-rich -and potentially habitable- environments were widespread during its early history [e.g., 1]. This important chapter in Mars' geologic history roughly spans one billion years, comprising the Noachian (4.1–3.7 billion years ago) and Hesperian (3.7–3.0 billion years ago) periods. During these two epochs, Mars experienced both the peak and the decline of its water activity. Indeed, each epoch’s aqueous processes have distinct mineralogical and geomorphological signatures whose succession indicates a trend toward aridity. In the Noachian, widespread valley networks [e.g., 2] and abundant clay minerals [3] point to sustained surface runoff and alteration by neutral-mildly alkaline water, suggesting a potentially “warm and wet” climate. By the Hesperian, sulfate evaporites [e.g., 3, 4] became more common, and valley network formation declined. Instead, isolated, large-scale floods from underground sources occurred, especially toward the era’s end [5]. These changes reflect reduced surface water and increasingly acidic conditions. The Noachian-Hesperian transition therefore marks an important turning point in the climatic history of the planet. Yet, its timing and characteristics are still poorly constrained. Study object and target area. The “Equatorial Layered Deposits” (ELDs) are defined as a variety of stratified sedimentary rock outcrops found globally in the Martian equatorial belt. ELDs are characterized by easily erodible hydrated minerals (commonly sulfates) and they can exhibit cyclical light and dark toned layering (Figure 1). The region of Meridiani Planum, hosts many examples of ELDs (here also historically referred to as “etched terrains” [6]) that formed around the Noachian-Hesperian boundary and which represent a key archive of Mars’ past climate. Overall, there is an ongoing debate regarding their formation processes, which remain uncertain [6,7].Figure 1. Equatorial Layered Deposits as seen by HiRISE (ESP_020138_1845) in Kai crater, Meridiani Planum. Arrows point at the alternating light and dark toned layers. Scientific objectives. We conducted a detailed analysis of the mineralogy and stratigraphy of the ELDs in selected areas of Meridiani Planum in order to better understand their possible formation processes and derive insights into Mars’ past climatic conditions at the Noachian-Hesperian boundary.Data and methods. Three relatively small (

Equatorial Layered Deposits (ELDs) are sedimentary landforms found at equatorial latitudes of Mars showing repetitive bedding and commonly associated with hydrous minerals. These deposits are important archives of Mars' past aqueous conditions yet in most cases their formation mechanisms are still debated and elusive. Here we provide a detailed characterization of the mineralogy and stratigraphy of three different exposures of ELDs in Meridiani Planum, where such formations are found within small impact craters and are dated back to the Noachian‐Hesperian boundary. Our analysis highlights a varying degree of mixture between polyhydrated Mg sulfates and Fe/Mg phyllosilicates within the beds of all three chosen targets, with several alternating strata of sulfate‐rich and phyllosilicate‐rich materials. In one case, Al‐phyllosilicates are also found along with their Fe/Mg counterpart. This is a much more varied mineral assemblage than previously reported for ELDs in this area. We propose a formation mechanism which explains the observed interbedding as a result of surface ponding of groundwaters, aqueous alteration of atmospherically‐sourced basaltic materials and water table/pH oscillations (wet/dry cycles) leading to recurrent sulfate precipitation. Our findings show how local environments play a substantial role in recording small‐scale variations of complex aqueous processes, generally not observed at regional and global scales on Mars.

Volcanic and magmatic processes have played a significant role in shaping Mercury’s surface and contributing to its mineral diversity. Areas such as smooth plains, which cover 27% of the planet, are thought to have formed from effusive volcanic events. Explosive volcanism is also suggested by the presence of depressions surrounded by high-reflectance halos, calderas, and vents linked to impact structures or faults. The BepiColombo mission, a collaboration between ESA and JAXA, was launched in 2018 to explore Mercury. It consists of two orbiters, MIO (JAXA) and MPO (ESA), with a focus on studying the planet's interior, surface, exosphere, and magnetosphere. The MPO carries instruments such as SIMBIO-SYS and MERTIS, which are designed to acquire spectral data.Interpreting planetary surface data often requires understanding complex factors like mineral composition, elemental abundance, temperature, and particle size. This study investigates the mid-infrared (MIR) spectral response of silicate glasses with a range of grain sizes and chemical compositions, aiming to build a database to support future spectral analyses of Mercury’s surface, where volcaniclastic materials are expected to be abundant.Three compositions resembling the Northern Volcanic Plains (NVP) on Mercury were prepared: NVP, NVP_Na, and NVP_Mg, each with varying amounts of Na and Mg. These compositions were created by melting pure oxides at 1400°C, then crushing the resulting glass into powder and re-melting it to ensure homogeneity. The glass was sieved into various grain size fractions, with some samples mixed to create new samples with Gaussian-like distributions to explore how fine-grained fractions affect spectral responses, particularly in relation to volcanic ash.Spectroscopic analysis was performed using a Bruker Invenio-X FT-IR spectrometer. The VNIR spectra (400-2000 nm) showed typical features of silicate glasses, with an absorption peak at around 1100 nm and a weaker one at 1900 nm, related to Fe-O bonds. The slope of the spectra did not vary much with increasing grain size in NVP samples, but there was a noticeable increase in the NIR slope (1200-1800 nm) for NVP_Na and NVP_Mg.In the MIR region (7-14 µm), the spectra revealed a correlation between the shape of the spectra and the chemical and granulometric characteristics of the samples. A local maximum at 10000 nm was observed for all spectra, associated with tetrahedral silicate units, and the NVP_Mg spectra showed distinct features due to the network-modifying role of Mg. The spectra also exhibited the Christiansen Feature at around 8 µm, a diagnostic feature for igneous products, and a transparency feature around 12 µm, which appeared in spectra of finer-grained samples.These spectra will be made available on the SSDC-ASI portal and will be crucial for interpreting data from the BepiColombo mission, particularly from SIMBIO-SYS and MERTIS. This research will help in identifying potential unknown igneous materials on Mercury’s surface.