## 3 Results and Discussion
### Marbles  
In the Table 2 the mineralogical, petrographic, and isotopic features of white and veined marbles are reported. Figure 5: Photographic documentation of yellow-brown patinas on marble cladding. FT-IR spectra of two analyzed patinas, samples L1_P4_H4 and L8_P1_H5: G, gypsum; Ox, calcium oxalate; S, silicate. Figure 6: Photographic documentation of dark brown patinas on marble. FTIR spectra of two samples are reported showing the presence of: (**a**) Ox, calcium oxalate; G, gypsum; OR, organic compound, microcrystalline wax. (**b**) Detail of the spectra between 500 to 1500 cm\({}^{-1}\): the dashed circles highlight the vibrational bands of microcrystalline wax. Figure 7: Raman and FT-IR spectra of the yellow-brownish patina: YO, yellow ochre; G, gypsum; Su, calcium sulphate; C, calcite; Ox, calcium oxalate. \begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline  
\begin{table} \begin{tabular}{c c c c c c c c c c c} \hline \hline
**Id Sample** & **Position** & **Mineralogical Composition** & **MGS** & \begin{tabular}{c} **Type of** \\ **Fabic** \\ \end{tabular} & \
\begin{tabular}{c} **Main Features of** \\ **Microstructure** \\ \end{tabular} &
\begin{tabular}{c} **Grain** \\ **Boundaries** \\ \end{tabular} & \(\boldsymbol{\delta^{13}}\)**C** & \(\boldsymbol{\delta^{19}}\)**O** & **Provenance** \\ \hline M20 & Side 4 & Calcite, Kleid +, quartz + & 1.5 mm & HE & Mortar & Straight/curved & 3.07 & \(-\)1.97 & Hymettus \\ \hline M21 & Side 1 & Calcite, dolomite, mica + & 2 mm & HE & Mortar, with deformed crystals & Curved/satured & 2.33 & \(-\)3.15 & Hymettus \\ \hline M22 & Side 6 & Calcite, quartz + & 500 \(\mu\)m & HO & Mosaic, polygonal & Straight & 2.07 & \(-\)2.22 & Carrara \\ \hline M23 & Side 4 & Calcite, quartz + & 500 \(\mu\)m & HO & Mosaic, polygonal & Straight & 2.00 & \(-\)2.08 & Carrara \\ \hline M24 & Side 4 & Calcite, dolomite +, quartz + & 500 \(\mu\)m & HO & Mosaic, polygonal & Straight & 2.21 & \(-\)2.02 & Carrara \\ \hline M25 & Side 9 & Calcite, dolomite +, quartz + & 2 mm & HE & Mortar, bimodal distribution & Curved/satured & 4.16 & \(-\)1.60 & Thassess/Provenance \\ \hline M26 & Side 6 & Calcite, dolomite +, mica + & 600 \(\mu\)m & HE & Lineated & Curved/embayed & 2.61 & \(-\)7.23 & Pentelicum \\ \hline M27 & Side 3 & Calcite, mica + & 700 \(\mu\)m & HE & Lineated & Curved/embayed & 2.54 & \(-\)7.03 & Pentelicum \\ \hline \hline \end{tabular}   
* *  
Only a multi-analytical approach allows us to identify, with good probability, the origin of a marble: the minero-petrographic analyzes of thin sections and the data from the stable C and O isotope ratio are the most consolidated methods [6; 27; 28; 29; 30; 31; 32]. Mineralogical and petrographic characteristics (microstructure, significant accessory minerals, maximum grain size (MGS) and boundary types of the calcite and/or dolomite crystals) are related to the provenance of marbles, since they are related to the type and degree of metamorphism undergone by the original sedimentary protolith. A first general fabric classification is based upon the equal or different dimensions of the calcite or dolomite crystals, referred to as homeoblastic (HO) or heteroblastic (HE) classification, respectively. The grain size is connected with the metamorphic grade and the MGS (maximum grain size) is reported in the most used database as one of the most diagnostic parameters. Moreover, the shape of the calcite or dolomite crystal boundaries reflects the blastesis/deformation relationships during a tectono-metamorphic event that generated marble crystallization [7; 8]. The isotopic ratios of C and O are related to the primary genetic (sedimentation) and evolutionary (diagenesis-metamorphism) processes that have affected the formation of marbles [33].