The rupture process in brittle materials is associated with tensile stresses at microscopic flaw scale inside their volume. Acoustic emission monitoring of diametral compression tests is an adequate option to assess the progression of damage. An improved algorithm for AE sources localization with P-wave velocity, v_p, calculation and an enhanced methodology for P-wave onset time, called CLAPWaVe [1], is applied to analyze the distribution of damage and the evolution of stiffness within monzogranite specimens. Complementary analyses allowed the identification of four zones of damage accumulation within the specimen volume, each of them with different cracking levels, absolute energy release, E_A, associated v_p values, induced by different phenomena occurring during the loading process. The observed non-homogeneous damage distribution confirms that using a unique v_p value to perform the localization of all AE sources, as usually adopted, is not representative of the real condition of the specimen.