The optical (UV–vis–NIR) spectra of fired Ni-geikielite pigments were consistent with the accommodation of Ni2+ ions
on octahedral A sites of ATiO3 ilmenite. Noteworthy,a noticeable increase of absorption intensity and bands’ broadening
was observed in the spectra of Ni-geikielite pigments fired at 1400 ◦C, which is responsible for the more intense colors and increased orange hue.This fact could be explained by a higher relaxation of the Laporte selection rule induced by an increased distortion or asymmetry of(Mg,Ni) O6 octahedra at this higher temperature.