In this study, the mechanism for the growth of manganese deposition on surfaces of magnesite ore is studied. For this purpose pictures of naturally occurring manganese dendrites of different forms encountered on samples of magnesite ore are obtained by a scanner; these pictures are used for computing the exponents of density correlation functions and fractal dimensions. The results imply that the limiting step in the formation of manganese deposition (dendrites) is a diffusion process. In order to test this hypothesis we have performed a fractal analysis of manganese dendrites using two different methods. The result yields that manganese dendrites have a self-similar structure and fractal dimensions vary within the interval 1.61-1.88. (c) 2005 Elsevier B.V. All rights reserved.