This work describes the coloration, chemical stability of SiO2 and SnO2-coated blue CoAl2O4 pigment. The CoAl2O4, raw materials, were synthesized by a co-precipitation method and coated with silica (SiO2) and tin oxide (SnO2) using sol-gel method, respectively. To study phase and coloration of CoAl2O4, we prepared nano sized CoAl2O4 pigments which were coated SiO2 and SnO2 using tetraethylorthosilicate, Na2SiO3 and Na2SiO3 as a coating material. To determine the stability of the coated samples and their colloidal solutions under acidic and basic conditions, colloidal nanoparticle solutions with various pH values were prepared and monitored over time. Blue CoAl2O4 solutions were tuned yellow color under all acidic/basic conditions. On the other hand, the chemical stability of SiO2 and SnO2-coated CoAl2O4 solution were improved when all samples pH values, respectively. Phase stability under acidic/basic condition of the core-shell type CoAl2O4 powders were characterized by transmission electron microscope, X-ray diffraction, CIE L*a*b* color parameter measurements.