## 4 Results and Discussion
### Ftir  
The FTIR spectra obtained from the samples display prominent peaks corresponding to aluminoisilicates and quartz, indicating the presence of these compounds (as shown in Figure 6). It should be mentioned that all the samples have been investigated on both faces (Ext = exterior; Int = interior), in order to identify all the small compositional changes. Because the area 3000-4000 cm\({}^{-1}\) indicate that the presence of hydrogen bonds can be found on the bands, which include amino, hydrate, and hydroxyl compounds, only the distinct molecular bands detected by FTIR will be taken into account, which were found at about 1645, 1463, 1000, 783, 562, and 460 cm\({}^{-1}\)[29; 32; 33]. The band at a wavelength of 1645 cm\({}^{-1}\) presents a nonlinear molecule with an O-H bond deformation (bending vibration) in the illite-mica minerals [44]. The appearance of a band at 1463 cm\({}^{-1}\) is assigned to CaCO\({}_{3}\)[45]. The most prominent peak, which mostly corresponds to quartz as a dominant component in the tested material, is found at 1000 cm\({}^{-1}\). The characteristic singlet and doublet, positioned at about 750-780 cm\({}^{-1}\), respectively, showed the presence of crystalline and amorphous forms of quartz. The band at 562 cm\({}^{-1}\) corresponds to trace amounts of hematite [44]. The stretching vibration associated with the band at about 460 cm\({}^{-1}\) is a Si-O-Si stretching vibration of quartz [46]. The FTIR spectra obtained from the samples display prominent peaks corresponding to aluminosilicates and quartz, indicating the presence of these compounds (as shown in Figure 6). The distinctive peak at 635 cm\({}^{-1}\) is attributed to hydroxyl groups, while vibrations at 694 cm\({}^{-1}\) along with doublets at 777 cm\({}^{-1}\) and 785 cm\({}^{-1}\) are characteristic of quartz, emphasizing its presence. The Si-O absorptions and bands at 436-440 cm\({}^{-1}\) further confirm the existence of quartz, with the broadband signal at around 1000 cm\({}^{-1}\) highlighting the crystalline nature of quartz within the samples. These spectral features provide valuable insights into the structure and composition for the analyzed ceramics [35]. The presence of bands at 797, 777, 510, and 440 cm\({}^{-1}\) in quartz indicates specific vibrational modes within the material, while the band at 1630 cm\({}^{-1}\) is assigned to the H-O-H bending of water molecules. Additionally, the FTIR spectra showed prominent bands related to silicates and aluminate hydrates, such as strong silicate bands at 1011-1022 cm\({}^{-1}\) and various internal bonds involving Si, O, and Al atoms. These observations provide valuable insights into the composition and structural characteristics of the sample [34]. The band at 694 cm\({}^{-1}\), attributed to the Si-O-Al group, Si-O-Si group, and Al-OH modes, suggests the presence of muscovite within the sample. Additionally, specific peaks at 563 and 476 cm\({}^{-1}\) indicate the presence of hematite in the studied region. These findings further support the characterization of the material and provide important information about its mineral composition [16]. In fact, the four samples clearly show the presence of quartz (1620, 1024, 785, 695, and 460 cm\({}^{-1}\)), calcite (1463, 874, and 713 cm\({}^{-1}\)), small amounts of albite (1024 cm\({}^{-1}\)), hematite (562 cm\({}^{-1}\)), and illite (1018 cm\({}^{-1}\)). Organic compounds and hydrate salts were not detected. Moreover, Fourier-transform infrared spectroscopy (FTIR) could be used to estimate the firing temperature of clay-containing remains, by taking into account the presence, position, and shape of specific infrared absorption peaks associated with clay minerals. The method is based on the findings on the infrared absorptivity of fired clay minerals, measured at the Si-O-Si stretching resonance band, knowing that the position of the main Si-O-Si absorption peak--the primary temperature indicator in most FTIR studies--does not always change continuously with increasing firing temperature.