## 3 Results and Discussion
### Mortars
\begin{table}
\begin{tabular}{l l l l l l} \hline \hline
**Mortar Samples** & **Depth** & **Binder** & **Aggregate** & **B/A** & **Macroporosity** \\ \hline \multirow{5}{*}{S13} & \multicolumn{3}{c}{Natural hydraulic} & Composition: quartz & & \\  & \multicolumn{3}{c}{lime and} & (monocrystalline), feldspar, rock & & \\  & \multicolumn{3}{c}{homogeneous} & fragments (micritic limestone, & \\  & \multicolumn{3}{c}{structure and} & \multicolumn{3}{c}{quartzite) and few fragments of} & \multirow{5}{*}{\(1/2\)} & High amount due \\  & \multicolumn{3}{c}{microsparitic} & \multicolumn{3}{c}{_cococipest_} & \\  & \multicolumn{3}{c}{texture.} & Heterogeneous grain size & & irregular shape \\  & \multicolumn{3}{c}{Recrystallized} & distribution & & \\  & \multicolumn{3}{c}{binder.} & Grain size 100 \(\upmu\)m–800 \(\upmu\)m & & \\  & \multicolumn{3}{c}{Some lumps} & Shape: sub angular & & \\ \hline \multirow{5}{*}{S14} & \multicolumn{3}{c}{Natural hydraulic} & Composition: quartz & & \\  & \multicolumn{3}{c}{lime and} & (monocrystalline), feldspar, few & & \\  & \multicolumn{3}{c}{heterogeneous} & fragments of carbonate rocks and & & \\  & \multicolumn{3}{c}{critic/microsparitic} & \multicolumn{3}{c}{_cociopest_} & \\  & \multicolumn{3}{c}{Homogeneous grain size} & & irregular shape \\  & \multicolumn{3}{c}{Some lumps} & \multicolumn{3}{c}{Station size 100 \(\upmu\)m–500 \(\upmu\)m} & \\  & \multicolumn{3}{c}{Shape: sub angular} & & \\ \hline \multirow{5}{*}{S15} & \multicolumn{3}{c}{Natural hydraulic} & Composition: quartz & & \\  & \multicolumn{3}{c}{lime and} & (monocrystalline), feldspar, few & & \\  & \multicolumn{3}{c}{heterogeneous} & fragments of sandstone rocks and & & \\  & \multicolumn{3}{c}{citric/microsparitic} & \multicolumn{3}{c}{_cociopest_} & \\  & \multicolumn{3}{c}{Homogeneous grain size} & & irregular shape \\  & \multicolumn{3}{c}{Recrystallized} & Grain size 100 \(\upmu\)m–500 \(\upmu\)m & & \\  & \multicolumn{3}{c}{Shape: sub angular/sub rounded} & & \\ \hline \multirow{5}{*}{S16} & \multicolumn{3}{c}{Natural hydraulic} & Composition: quartz & & \\  & \multicolumn{3}{c}{lime and} & (monocrystalline), feldspar, & & \\  & \multicolumn{3}{c}{heterogeneous} & fragments of sandstone, few & & \\  & \multicolumn{3}{c}{structure and micrite/microsparitic} & \multicolumn{3}{c}{_cociopest_} & \\  & \multicolumn{3}{c}{texture.} & Homogeneous grain size & & irregular shape \\  & \multicolumn{3}{c}{Recrystallized} & distribution & & \\  & \multicolumn{3}{c}{binder.} & Grain size 100 \(\upmu\)m–500 \(\upmu\)m & & \\  & \multicolumn{3}{c}{Some lumps} & Shape: sub angular & & \\ \hline \hline \end{tabular}
\end{table} 
Table 4: _Cont._superficial sample), S12, and S13. Vaterite was typically found in the Florentine mortars, associated with the production of natural hydraulic binders obtained by burning marly limestone [17; 19; 37]. The presence of portlandite (Ca(OH)2) in the deepest sample of S4 was noted, linked to an incomplete carbonation of binder. Gypsum was registered only in S13, belonging to the basement, most probably due to the sulphation phenomena of the binder. The petrographic observation (Table 4) performed on Baptistery mortar samples shows, mainly, a binder with a heterogeneous structure and micritic/microsparitic texture, as well as the presence of lumps, both as remnants of the binder not being well mixed and as remnants of overburnt limestone fragments. An exception is represented by S12 sample, which came from the basement, collected from the mosaic masonry, composed of lime hydraulicized with crushed ceramics. In some cases, the binder of the mortars was subjected to processes of dissolution and recrystallization by aqueous solutions circulating in the masonry, and occurred inside the pore space. The recrystallizations are present in the majority of samples, except in S1, S3, S14, S17, and in the internal samples S5, S7, and S8. Often, the absence of dissolution and recrystallization phenomena is correlated to the homogeneous characteristic of the binder, as shown in samples S3 and S14.