This study described the microstructural features of the mortar-rock composites. The specimen of the composite has been prepared using Kota stone and cement mortar. Cement mortar contains three grades of sand in equal proportion as per IS (650). X-ray tomography was utilized to explore the porosity and to reconstruct the interface between stone-mortar. 2D X-ray slices were used to reconstruct the realistic 3D microstructure of the composite. The pores and interface are segmented using gray scale values and manual intervention. The cut-off value for the porosity is decided based on the hysterogram of gray scale. The histogram of the equivalent diameters of the voids is obtained. The porosity of the mortar is measured as 1.465% and most of the pore’s diameters range in between 0.1 to 0.4 mm in size.