This work presents theoretical and experimental X-ray diffractometry investigations of the morphology and deformation state of calcium hydroxide (Ca(OH)(2), CH) crystallites in the interfacial transition zone of concrete. Based on the developed theoretical approach, the distributions of CH crystallites and their coherent domains over strains and sizes are reconstructed. The average amounts of planar defects, cracks, and possible stacking faults within a CH crystallite are estimated. A comparative analysis is conducted for the morphology of CH texture depending on the type of aggregate particles (granite and smoky quartz) used.