The invention is directed to a process for the manufacture of a ceria based polishing composition, comprising (a) suspending an inorganic cerium salt or cerium hydroxide with a cerium content calculated as cerium oxide in the range of 50%-100% based on Total rare earth oxide (TREO) in an aqueous medium thereby obtaining an aqueous suspension, (b) treating said aqueous suspension with an acid or a salt of an acid selected from the group of HF, H3PO4 and H2SO4, thereby obtaining a solid suspended in said aqueous medium, (c) separating said solid from said aqueous medium, and (d) calcining the separated solid at a temperature between 750° C. and 1,200° C. and grinding the calcined solid to grain sizes in the range of 0.5 μm to 5.0 μm.