The two glass-ceramics studied here derive from the complex system (MgO,ZnO,Li2O)-Al2O3-SiO2 and are obtained by controlled devitrification of the same parent glass. Although they have the same chemical composition, one is a "beta-quartz" (or "beta-eucryptite") type while the other one is a "beta-spodumene" glass-ceramic. A detailed microstructural analysis of these materials has been performed at different scales by several complementary characterization methods (SEM, TEM, DTA, XRD and FTIR). This extensive study has shown the great microstructure difference (grain distribution, grain size, nature of vitreous and crystalline phases) between these two glass-ceramics obtained from the same parent glass.