The present work shows experimentally the evolution of grain microcracks and residual stresses of the sintered β-eucryptite material going through many thermal fatigue cycles (∼3600). The effect of stresses applied on β-eucryptite crystals due to the thermal cycling could be considered for explaining the small change observed of β-eucryptite to β-spodumene phase, which is higher in the samples obtained by microwave sintering. Therefore, the study of residual stresses has suggested that the heating source employed, such as conventional or microwave, has a great influence on thermal fatigue life and the final mechanical and thermal properties. The microwave heating has a significant impact on β-eucryptite materials lifetime.