New nano-blue ceramic pigments of CoxMg1−xAl2O4 (0 ≤ x ≤ 0.1) have been prepared by co-precipitate–combustion as a hybrid method using urea as a fuel at 500 °C in open furnace in air atmosphere. The structure of pigment is assigned based on TGA/DTA/DrTGA analyses, X-ray diffraction (XRD) and transmission electron microscopy (TEM). Also, electronic spectra, infrared (IR) and diffuse reflectance spectroscopy (DRS) using CIE L*a*b* parameter measurement techniques were used. The results revealed that the nano-particle size of pigments were obtained in the range 30–38 nm as well as the varying colors and particle size as a result of different calcinations temperatures within the range of 500–1200 °C for 2 h.