## 3 Materials Used for Restoration and Conservation of Masonry Elements
### General Considerations
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Class** & **Type** & **Examples** & **Composition** & **Characteristics and Uses** & **Ref.** \\ \hline \multirow{4}{*}{Intrusive rocks} & \multirow{2}{*}{Felsic} & \multirow{2}{*}{Granite} & Quartz (20\%-60\%), felspars, mica; & Granular, phametic, massive, hard and tough. Average & \multirow{4}{*}{[41]} \\  & & & ratio plagioclase+\(\overline{\text{A}}\)kali & density 2.65 and 2.75 g(cm\({}^{3}\), compressive strength \(>\)200 & \\  & & & & MPa; used for the construction of pyramids, lumms, door & \\  & & & feldspar) \(>\) 10-65 & linlets, sills, wall coverings; mostly used as size stone & \\ \cline{2-6}  & \multirow{2}{*}{Intermediate} & \multirow{2}{*}{Diorite} & \multirow{2}{*}{Diorite} & \multirow{2}{*}{\begin{tabular}{c} plagioclase feldspar, biotite, \\ hornblende, pyroxene \\ \end{tabular} } & \multirow{2}{*}{\begin{tabular}{c} Pharentic, occasionally porphyite, extremely hard, \\ usually used for sculptures, roads, drainage or microsptions \\ \end{tabular} } & \multirow{2}{*}{[42]} \\ \cline{2-6}  & \multirow{2}{*}{Mafic} & \multirow{2}{*}{Gabbro} & \multirow{2}{*}{\begin{tabular}{c} Plagioclase and clinopyroxene \\ \end{tabular} } & & Used as ornamental facing or paving stones & \\ \cline{2-6}  & & & & \\ \cline{2-6}  & \multirow{2}{*}{Ultramafic} & \multirow{2}{*}{Peridotite} & \multirow{2}{*}{Olivine and pyroxene} & & Coarse-grained, dense, uncommon at the surface, unstable, \\  & & & & rarely used & \\ \hline \multirow{4}{*}{Extrusive rocks} & \multirow{2}{*}{Felsic} & \multirow{2}{*}{Rhyolite} & Quartz (\(>\)20\%), alkali feldspar & Very viscous; used as building, facing or paving stone. & [44] \\  & & & (\(>\)35\%) & & \\ \cline{2-6}  & \multirow{2}{*}{Intermediate} & \multirow{2}{*}{Andeste} & \multirow{2}{*}{Plagioclase, pyroxene, homblende} & Porphytic structure, density 2.11–2.36 g/cm\({}^{3}\), used as filling material, for sculptures or momounts & \\ \cline{2-6}  & & & & \\ \cline{2-6}  & \multirow{2}{*}{Mafic} & \multirow{2}{*}{Basalt} & Pyroxene (augite), plagioclase, & Aphanatic, the most encountered volcanic rock, used as building blocks, cobbiststones, for states & \\ \cline{2-6}  & & & & & \\ \cline{2-6}  & \multirow{2}{*}{Ultramafic} & \multirow{2}{*}{Komatite} & \multirow{2}{*}{\
\begin{tabular}{c} Olivine, pyroxene, anorthite, \\ chromatic \\ \end{tabular} } & & &
\begin{tabular}{c} Spinire texture, rare, not usually used for traditional \\ construction \\ \end{tabular} & & [47] \\ \hline \multirow{4}{*}{Sedimentary rocks} & \multirow{2}{*}{Clastic} & \multirow{2}{*}{Sandstone} & \multirow{2}{*}{Quartz or feldspar} & Grain size, 0.06–2 mm, variable hardness and color; versatile uses (dependent on the & [48, 49] \\  & & & & composition)–construction, decoration & \\ \cline{2-6}  & \multirow{2}{*}{Biochemical} & \multirow{2}{*}{Limestone} & \multirow{2}{*}{Calcite and aragonite} & Variable grain size and texture, hard; used for buildings, decorations or mortars & \\ \cline{2-6}  & & & & & \\ \cline{2-6}  & \multirow{2}{*}{Chemical} & \multirow{2}{*}{Gypsum} & Calcium sulfate dihydrate & Variable color and luster, Mohs hardness 2, specific gravity & \\  & & & & 2.31–2.33; used for plasters, decorations & \\ \hline Metamorphic rocks & \multirow{2}{*}{Marble} & \multirow{2}{*}{Calcite or dolomite} & Usually white, medium grained, hard, relatively abundant; used for buildings, decorations, sculptures or flooring & & [52] \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Characteristics of natural rocks used in verrancal constructions.