Effect of Beryllium Heat Treatment in Synthetic Ruby

We study the effect of Be atoms in the corundum structure by using UV-Vis–NIR spectroscopy as well as X-ray absorption spectroscopy on synthetic ruby samples obtained by the Verneuil process. From the X-ray absorption near edge structure (XANES) spectra, the Be atoms are shown not to be related to the Cr environment. Furthermore, the UV-Vis–NIR absorption spectra are similar for the unheated, traditionally heated, and Be-heated synthetic ruby samples. However, the Be atoms are able to produce a brown-colored center, and the mixing of the red and the brown colors yields the orange in the Be-heated synthetic ruby samples. We propose that the orange color in the Be-heated synthetic ruby samples is caused by the Be2+ donor state at 475 nm (2.61 eV) in multiple UV-Vis–NIR wavelength excitation spectra.