## Appendix A
### Remament Magnetization in Ceramic Fractures
From the experimental results it can be concluded that the sensors are detected the magnetic field of a cylindrical area of the ceramic material, whose dimensions depend on the magnitude and the directionality of the remanent magnetization, the fragment thickness, and finally the sensor position. For the remainment magnetization computation from the magnetic field measurements, the readings of the vertical sensor are adjusted, because of its smaller sensitivity degree, compared with the parallel ones. Investigation of the Range and Anisotropy Degree of the Ceramic Region That Produces the Magnetic Field, Which Is Detected by the Sensors  
The three-dimensional orthogonal system layout of sensors/magnets (Figure 10) remains in the same position with respect to the geomagnetic field, with \(x\)-sensor (B\({}_{x}\) = 0) being perpendicular to the horizontal and vertical constituent of the geomagnetic field. The vase fragments are supported on a horizontal disk at a position where B\({}_{y}\) = 0 and B\({}_{x}\) = B\({}_{xy}\) \(>\) 0. Measurements are taken with every 30\({}^{\circ}\) rotation of the disk, \(\varphi_{\delta}\), from 4 irregularly-shaped co-belonging fragments, 2 from the vase and 2 from body, for each of the 6 vases. Figure 10: Illustration of the experimental apparatus and measured components of the field **B** in the considered coordinate system by the three-dimensional orthogonal system layout of sensors/magnets. With every rotation of the disk, the magnitude \(\mathrm{B}=\sqrt{\mathrm{B}_{\mathrm{x}}^{2}+\mathrm{B}_{y}^{2}+\mathrm{B}_{ \mathrm{z}}^{2}}\), angle \(\mathrm{\theta}_{\mathrm{B}}=\cos^{-1}\frac{\mathrm{B}_{\mathrm{z}}}{\mathrm{B }}\) and angle \(\mathrm{\varphi}\ =\ \tan^{-1}\frac{\mathrm{B}_{y}}{\mathrm{B}_{\mathrm{z}}}\), which is compared with the disk rotation angle \(\mathrm{\varphi}_{\delta}\), are computed from the sensor readings, \(\mathrm{B}_{\mathrm{i}}\) (i = x,y,z). At the rotation positions of the base and body fragments (Table 1), the computed angle \(\mathrm{\varphi}\) is close to the measured disk rotation angle \(\mathrm{\varphi}_{\delta}\). The sensors do not take measurements from the total shell area but rather from a restricted, rotationally symmetric area around the z-axis, which can be considered magnetically isotropic. For this reason irregularly shaped fragments from the vase and neighboring body fragments are oriented in a manner that they join. In contrast to the co-belonging, and of similar thickness, base fragments (Charts A1 and A2), the values of \(\mathrm{B}_{\mathrm{z}}\), \(\mathrm{B}\), \(\mathrm{\theta}_{\mathrm{B}}\) vary in the vase body. The large deviations in the magnetic field magnitude of the co-belonging body fragments cannot be attributed to the differences in the thickness or the magnetic anisotropy of the ceramic material, since in the case of base fragments, of the same material and indeed of irregular shape, it displays similar values. **Chart A1. ** Change in the computed angle \(\theta_{\text{B}}\) at disk rotation angles \(\varphi_{S}\) in 2 base fragments (**a**) and 2 body fragments (**b**). **Chart A2. ** Change in the measured component B\({}_{\text{z}}\) and computed magnitude, B, of the magnetic field at disk rotation angles \(\varphi_{S}\), in 2 fragments (\(\beta\)3,\(\delta\)3) of the base (**a**) and 2 fragments (B1,Z7) of the body (**b**) of wave 1. Investigation of the Contribution of the Ceramic Material Induced Magnetization in the Magnetic Field Measurements  
From the base fragments which display similar magnetic field, cylindrical specimens are constructed (Figure A4) and sliced into equilateral tiles.