The synthesis of a newnano-blue ceramic pigment CoxMg1−xAl2O4 (0≤x≤0.1) using the combination between co-precipitation and combustion synthesis (CS) method. The structure of pigments is assigned based on thermogravimetric and differential thermogravimetric analysis (TG-DTGA), X-ray diffractions (XRD), and UV–vis spectroscopy. Also, diffuse reflectance spectroscopy (DRS) using CIE L*a*b* parameter measurement method, infrared spectroscopy (IR) and transmission electron microscopy (TEM) is used. The result revealed that the nano-size particle pigment was obtained in range 24–35 nm by using 3-methyl-pyrozole-5-one (3MP5O) as a fuel at 400 ◦C in open furnace. Also, results show the varying colors and particles’ size as a result of different calcination temperatures from 500 to 1200 ◦C for 2 h.