## 4 Results and Discussion
### Microscopy  
An optical microscopy analysis of the samples revealed fine crystal-like traces, distinct groove-type patterns, as well as a cracked texture, indicating specific characteristics and formations present in these ceramics. The detailed observations in the optical and stereomicroscopic images provide insight into the composition and structure of the ceramic bodies, with previous studies suggesting that the ceramics are made from semi-fine clays with an amorphous microcrystalline structure containing non-plastic natural inclusions, either from raw materials or added during processing. These findings contribute to a better understanding of the manufacturing processes and material composition of the studied ceramics [5; 16; 19; 20]. In this case, the non-plastic inclusions found in the ceramics primarily consist of materials such as quartz, muscovite, hematite/goethite, and feldspar group clays, with sizes ranging from 1 to 3 mm and accounting for 5% to 10% of the shard volumes. These inclusions also include components like calcite, hematite, and even small plant remains within the sherds. Notably, red ober, soot, hematite, and possibly maghemite were identified in the red and black decorations of the Neolithic pottery from southern Romania, serving as indicators of firing conditions and providing valuable insights into the cultural and technological aspects of the ceramics studied [31]. All these inclusion, more visible by stereomicroscopy, have been identified as small fragments of reddish, black, or intermediate colors, visible in sample PI's red part, while, in the black part, this color seems to be deposited, most probably due to an anaerobic firing atmosphere, or to the obtained soot, as can be seen in Figure 5g,h. The same observations could be not so visible for sample P2, as can be seen in Figure 5i,j. Except for the quartz identified in the ceramic sherds, mica fragments that are light-colored (yellow-greenish) have been observed like minerals with potassium and aluminum, and those known as clayed mica, which are yellow-greenish colored, as hexagonal elastic sheets, organized in scaly aggregates, according to the literature [6]. The analysis revealed that various Fe-rich minerals were present in the red colors of the ceramics, while dark brown hues were predominantly achieved using Mn-rich minerals, as other researchers in Neolithic pottery from different locations across the Balkans and Europe highlighted the potential similarities and shared practices in pigment preparation and decoration techniques during that period [32; 33]. The SEM micrographs displaying representative samples of vessel sherds can be viewed in Figure 5k-m, providing a visual insight into the characteristics and composition of the analyzed samples. These micrographs likely offer detailed information on the surface morphology, elemental composition, and structural features of the vessel sherds, aiding in the further understanding and interpretation of the materials under investigation. For sample P1, only the red part presented significant structures, not the black part. Being a non-calcareous ceramic, with a low concentration of CaO heterogeneous distributed in the ceramic mass, in sample P1, a zone dominated by nanometric pores (Figure 5k,l) was observed inside the calcite crystals, which suggests an early stage of decomposition and release of CO\({}_{2}\), as demonstrated by [PERSON] et al. [34]. The entire surface of calcite crystals exhibits nano-porosity, which is primarily concentrated along the weaker regions of the crystals called cleavage surfaces. The combustion of the coal mass dispersed in the sample may be a source of these pores. The amorphous glassy mass together with cryptocrystalline minerals is organized in the pore walls of the boundary layer (Figure 5m), where some spherical aggregates can be formed, and their size makes the pore walls even more visible (Figure 5n). Obviously, such an organization contributes to the increase in porosity, decreasing the water absorption capacity of the ceramic vessel [35].