## 3 Results
### Raman Spectroscopy  
For each sample, spectra of the leucocratic and melanocratic fractions are collected. Table 4 presents a schematic synthesis of the results for each sample analysed including the hypothesis of the lithological category to which each sample might belong. Figure 7: **(a)** The comparison of the R3 sample 3D model in Agisoft Metashape rendering **(left)** and the R3 sample 3D model in Sketchfab **(right)**; **(b)** In Sketchfab visualisation, the comparative display of R4 sample 3D model deriving from non-processed photographs **(left)** and R4 sample 3D model from processed photographs **(right)**. Dark lines highlight the superficial curvilinear engravings. From the mesoscopic observation, the samples show high variability in the quantity of the leucocratic and melanocratic fractions. R4 has the highest percentage of the leucocratic fraction which is also evident through its light colour. Regarding the rock structure, R1, R2, and R5 show a moderate foliation. This feature in R2 is observable especially in the two fracture surfaces whereas in R1 and R5 the foliation is highlighted by the preferential spatial orientation of the melanocratic fraction. A preferred orientation of melanocratic minerals is not detectable in R3 and that condition determines the casual fabric of the entire fragment. In contrast with the other samples, the R4 fracture surfaces show a foliation oriented with the profile of its lateral sides. The Raman spectra analysis shows that the leucocratic fraction of sample R1 mainly consists of prehne (Ph) and calcite (Cal) while its melanocratic fraction is made of pyroxene and a low percentage of amphibole. The proof of the pyroxene and amphibole discrimination is reported in Figure 8a. Prehnite is an inosilicate of calcium and aluminium resulting from a low-grade metamorphic process, defining the HP-LT metamorphic prehnite-pumpellyite facies. The water content in the prehne structure determines the characteristic peak at about 3600 cm\({}^{-1}\) (Figure 8b), which confirms its mineralogical attribution. Calcite in metamorphic rocks is a common mineralogical phase deriving from the transformation of sedimentary protolith containing calcium carbonate. The acquired spectra of calcite highly match the reference spectrum from the RRUFF database (Figure 8b). R1 may be classified as metabasite, deriving from the metamorphism of a basaltic protolith, a basic rock rich in calcium, iron, and magnesium. Sample R2 predominantly consists of calcite along with a low content of orthoclase and amphibole with epidote. The An(mol%) content is approximately \(23\pm 4\%\), so plagioclase in R2 belong to the Na-rich albitic extreme of the plagioclase solid solution. Epidote and amphibole discrimination is conducted using the fingerprint interval and the different collocation of the hydroxyl groups in the 3200-3800 cm\({}^{-1}\) region (Figure 8c). The abundance of calcite associated with epidote, a metamorphic mineral, supports the hypothesis that R2 may be a silicate marble or possibly a calscchist. Considering the leucocratic fraction of samples R3 and R5, it is predominantly made of plagioclase with a respective An(mol%) content of 33 \(\pm\) 7% and 47 \(\pm\) 7%. Nevertheless, the percentage of RR5 An(mol%) content does not faithfully represent its bimodal distribution. As the graph in Figure 9 shows, MFP plagioclase composition consists of two domains, the first one at the lower percentage value of 20% and the second one at about 60%, so the Gaussian distribution has a high variance. For this reason, even if the mean value reveals that plagioclase in R5 are albitic (rich in Na), the Ca presence may not be excluded. The average percentage of An(mol%) content in R3 represents the distribution of single values