In this paper. electrokinetic potential and isoelectric point of dolomite (CaMg(CO3)2) and magnesite (MgCO3) were determined. The effect of various ions such as Mg2+, Ca2+, Na+ and CO32- on surface properties of dolomite and magnesite were also examined. Isoelectric points of dolomite and magnesite were determined as 6.3 and 6.8, respectively, in the absence of any electrolyte. H+ and OH- ions are the potential determining ions of magnesite and dolomite, as predicted by electrokinetic potential studies. (c) 2005 Elsevier B.V. All rights reserved.