Dolomitic talc was milled in a mortar mill by varying the milling time, solid content, and vertical stress. The milled samples exhibited massive particle size reduction and came to a threshold value around 4 mu m, with wider particle size distribution. The breakage mechanism of the dolomite and talc phase was influenced by hardness, crystallographic structure, and Young's Modulus. The milled particles underwent massive mechanochemical effect where the degree of crystallinity ranged from 40% to 50%. The variation of lattice parameters of both phases was influenced by mill operational parameters and breakage mechanism of the particles in the mill. (C) 2010 Elsevier B.V. All rights reserved.