## 4 Results and Discussion
### Thermogravimetric Analysis (TGA/DTG)  
The thermal behavior of the samples was examined as depicted in Figure 8. The firing temperature determination was conducted by analyzing the light-colored regions (ranging from yellow to red) and comparing them with controlled fired clay samples of a similar nature, demonstrating a firing temperature range spanning from 500 \({}^{\circ}\)C to 700 \({}^{\circ}\)C. By  
Figure 7: The Raman spectra of P1 (**up**) and P2 (**down**) samples. leveraging this comparative approach, insight into the firing conditions and temperature ranges employed during the production of the samples was successfully obtained. The thermal analysis conducted within the temperature range of 100-250 \({}^{\circ}\)C was an indicator for removing of the absorption water specific to each clay deposit, while the elimination of chemically bound water took place around 400 \({}^{\circ}\)C. It is crucial to control the temperature escalation beyond these critical points, as rapid heating towards values near the maximum tolerance level of each clay type could potentially result in the vitrification of the clay mass and deformation of the pieces. The attribution of firing temperatures, such as the suggestion of 600 \({}^{\circ}\)C for achieving a light brown color, highlights the importance of precise temperature control in the production process to attain the desired ceramic properties. The study's findings, revealing low calcium concentrations and the absence of calcite, are indicative of lower firing temperatures, providing valuable insights into the firing conditions necessary for optimal ceramic outcomes. Iron oxides play a significant role in the coloration of ceramics during firing. The colors produced, ranging from rust-red to dark brown or black, depend on the concentration of iron oxide and the firing conditions. The atmospheric conditions, such as the presence of oxygen in the kiln, can impact the chemical reactions involving iron oxides, influencing the final color of the ceramics. In oxidation firing, where there is sufficient oxygen, iron oxide tends to be refractory and does not melt well, resulting in lighter colors. In reduction firing, with limited oxygen, iron oxide acts as a strong flux, creating a more fluid glaze with darker colors [56, 57]. Sample P1 exhibits red and trifite exteriors with partially black insides, showcasing variations in color transformation under different combustion environments. The red engobe experienced similar alterations to the shard's core while showcasing color changes under oxidizing conditions. Within the same engobe type, diverse shades of red were observed. The presence of carbon deposition in vessel pores can affect the external color of white pigment in ceramic samples by potentially altering the purity and brightness of the white color due to the darkening effect of carbon. Different combustion conditions leading to varying levels of carbon residue can impact the overall appearance and properties of the ceramic material, potentially affecting its optical characteristics and surface quality [58]. The presence of calcite in ceramic samples can provide information about the firing temperature and combustion conditions used in their production. The presence of calcite indicates low firing temperatures (650-800 \({}^{\circ}\)C) characteristic of bonfire firing technology in a reducing atmosphere. The chemical composition and mineralogical differences in the samples can further support these temperature and combustion condition assessments. The presence of iron oxides, such as hematite (\(\alpha\)-Fe\({}_{2}\)O\({}_{3}\)) or magnetite (Fe\({}_{3}\)O\({}_{4}\)), in ceramic samples can provide valuable information about the firing atmosphere in which they were  
Figure 8: TGA (red line) (**left**) and blue line (**right**) and DTG (black line) for the samples P1 and P2 (heating rate 10 \({}^{\circ}\)C/min). produced.