Table : ζ-potential and hydrodynamic sizes of particles synthesized under different conditions of C P , C S and β. It shows increases in C P and β produces large, less colloidally stable, and aggregated particles. However, increasing additive Ca 2+ concentration (C S ) produces relatively small particles in low C P and β conditions. The ζ-potential could not be measured in certain cases, particularly when C S = 0 mM, as the particles are large aggregates which rapidly sediment. This is also why hydrodynamic sizes of some particles synthesized when C S = 0 mM were not measured. C S = 0 mM represents cases where the precipitates were dispersed in ultrapure H 2 O. ), though the hydrodynamic size is ∼3 µm (Table ). This aberration is attributed to a known demerit of the DLS method. Besides assuming a spherical shape for the dispersed particles, the presence of aggregates in the sample immensely affects the measurement accuracy. The colloidal stability of the particles, as inferred from their ζ-potential, generally im- proves with increasing C S . It is worth noting that the positive ζ-potential indicates that additive Ca 2+ ions indeed adsorb on the CaCO 3 precipitates (Table ). Therefore, for a given β and C P condition, increasing C S should also improve the ζ-potential of the particles.