Interfacial chemistry, particle size, morphology, and mineralogy play a pivotal role in the rheological behavior of mineral dispersions. In this study, interfacial chemistry and particle interactions of polydispersed chlorite clay dispersions as a function of pH, solid content and solution speciation have been investigated in the pH range 2-9 at 25ºC. Particle zeta potential, reflecting interfacial chemistry indicates a strong pH history dependency. The Electrokinetic potential measurements show that the chlorite particles are moderately charged (~ -25 mV) at pH >9 with an isoeletric point around pH 5 during the sweep of pH from high to low value. A bifurcation is observed as the pH was increased from low (e.g. 2) to high value (e.g. 9), indicative of pH – modified interfacial chemistry. Particle interactions measured through dispersion shear yield stress analysis show a similar pH - history dependency. Supernatant analysis suggests that the suspension pH dependent behavior may be attributed to the release of Mg, Fe, Al and Si ions as a result of chlorite leaching at lower pH. Formation and specific adsorption of hydrolysed metal complexes onto particles which occurs at higher pH are consistent with the observed interfacial chemistry and particle interactions. The findings enable us to accurately rationalize the nature of the force underpinning particle network structure and strength during aqueous processing of clay-based mineral dispersions.