Crystallization of basalt fibers containing 0-7 wt%ZrO2 was studied. Fibers were drawn from basalt glasses and annealed in air at different temperatures. Phase composition of obtained samples was determined by XRD. Kinetics of crystallization processes was investigated by DSC. Kinetic models and parameters were estimated for crystallization of spinel-like phase, pyroxene and plagioclase using model-free analysis. It was found that doping of fibers with 1-3 wt% ZrO2 increased Arrhenius parameters of aluminosilicate crystallization. When the zirconia content was 5-7 wt% the crystallization mechanism significantly changed. This phenomenon resulted in increasing of fiber thermal stability. (C) 2013 Elsevier B.V. All rights reserved.