The crystallization mechanism of the glass-ceramics obtained from Romanian (Şanoviţa) basalt in the presence of 3 and 5% CaF2 as nucleation agent has been investigated under non-isothermal conditions using DTA technique. The activation energies of
the crystallization processes were calculated using the Kissinger-Akahira-Sunose, Ozawa-Flynn-Wall, Starink and Tang isoconversional
methods. The monotonous decreases in the activation energy (Ea) with the crystallized fraction (α) confirms the complex mechanism of the glass-ceramics crystallization process. It has
been proved that the Johnson-Mehl-Avrami model cannot be applied for the studied glass-ceramics crystallization process.