## 3 Results and Discussion
### Monochrome Colored Glazes  
Colored glazes were used for coating always both ceramic sides. Yellow/honey glazed samples were decorated on both sides of the objects with the same color; however, green glazed fragments were decorated with either green or yellow glazes on the secondary side. Compositional analyses of green and yellow monochrome glazes (Table 4) revealed that they were rich in lead and silicon, with minor quantities of iron, aluminum, calcium, and alkali oxides. Similar chemical compositions were determined on the secondary sides. Only slight compositional differences were observed among green and yellow glazes. Some of these differences were due to elements responsible of the color of glazes. Although the final color of glazes was also influenced by the body color and the metallic oxide added into the glaze [12; 14; 17], the latter was the responsible of the compositional differences. Therefore, yellow/honey glazes had higher amounts of FeO (1.6-4% in yellow glazes, versus 0.6-1.7% in green glazes) and green coatings were richer in CuO proportions (1.2-4% in green glazes). An important feature of these monochrome glazes was the fact that all green glazes included tin oxide in their composition (Table 4). Tin was detected with EDS analysis and tin-oxide crystals were observed in the green glazes. Although the tin-oxide percentages were lower than white tin-opacified glazes (Table 3), the proportion was enough to give a certain opacity. This characteristic was also highlighted in green glazes from Zaragoza _Taif_[22]. Inclusions were occasional in the main monochrome glazes (Figure 5), but they were always present in the secondary sides, which implied careful treatment of raw materials again, especially for the main sides. These inclusions were mainly quartz and feldspars. It is not easy to establish an average size of the inclusions because there was a lot of variation even inside the same specimen. The glaze thickness was quite constant in the same sample, but it varied significantly among different ceramic fragments. Additionally, not only the yellow/honey glazes but also the green glazes were thicker in the main side (100-150 um for the yellow glazes, and 150-200 um for the green glazes) than in the less important side (80-100 um in the yellow glazes, and 100-150 um in the green ones). \begin{table}
\begin{tabular}{c c c c c c c c c c c c} \hline
**Glaze** & & **Na\({}_{2}\)O** & **MgO** & **Al\({}_{2}\)O\({}_{3}\)** & **SiO\({}_{2}\)** & **K\({}_{2}\)O** & **CaO** & **FeO** & **CuO** & **SnO\({}_{2}\)** & **PbO** \\ \hline honey & _mant_ & 0.54 & 0.94 & 5.00 & 37.8 & 2.10 & 5.03 & 2.59 & - & - & 45.1 \\ _s (m = 19)_ & _0.24_ & _0.29_ & _0.72_ & _1.4_ & _0.46_ & _1.44_ & _0.74_ & & & 3.7 \\ \hline green & _mant_ & 0.94 & 0.74 & 4.53 & 40.4 & 2.84 & 3.98 & 1.17 & 2.56 & 1.80 & 41.0 \\ _s (m = 17)_ & _0.36_ & _0.21_ & _0.79_ & _3.5_ & _0.78_ & _1.05_ & _0.35_ & _0.85_ & _1.71_ & _4.5_ \\ \hline \end{tabular}
\end{table} 
Table 4: Chemical composition (%wt) of monochrome glazes by EDS. In these types of glazes, greater interactions between body and glaze were observed by SEM (Figure 5a). Since the reaction between ceramic paste and glaze was related with the type of developed firing process [12; 17; 21], it can be assumed that the thickness of the interface (35-40 \(\upmu\)m) in monochrome glazes corresponded to a single firing process. This technique of manufacture justified the great amount of lead-potassium feldspar crystals that existed in the interface, and that favored the adhesion between both layers [23]. In addition, this type of firing process enhanced the diffusion of certain elements (such as aluminum and iron) from the body to the glaze. Aluminum and iron were incorporated into the glaze and helped the stabilization of PbO-SiO\({}_{2}\) glazes. Therefore, the presence of aluminum and iron in the glazes can be attributed, on the one hand, to the raw materials of the glazes and, on the other hand, to the diffusion of components from the clay to the glaze during the firing process [12; 17].