The kinetics of calcite (CaCO3) crystallization on calcite in the presence of titanocene, zirconocene, vanadocene, hafhocene dichlorides and ferricenium salts was investigated by the constant composition technique. The rates of crystal growth measured in the presence of metallocene complexes at concentrations 2.60-4.02 x 10(-5) mol dm(-3) were drastically reduced by 27-66%, possibly through adsorption onto the active sites of crystal growth. Kinetics analysis suggested a surface diffusion controlled spiral growth mechanism. (C) 2002 Elsevier Science B.V. All rights reserved.