Abstract The thermal process has been adopted for the synthesis of the yellow pigment Zr 1−xPr xSiO 4 from the starting oxides ZrO 2 and SiO 2. The reactions of the synthesis have been followed by thermal analysis, analysis of the products prepared in the electric furnace under various conditions (temperature, time) and tableting (labelling) experiments. The two types of ZrO 2 used are those also currently utilized in the industrial production of the zircon pigments. Their reactivity has been evaluated and the synthesis conditions have been determined. The kinetics and mechanism of the reactions are also discussed.