Implanting photoactive ions into quartz or silica is a simple and efficient way to tune the luminescence light used for various optoelectronic applications. However, such ion implantation damages or even destroys the crystalline order in quartz. We report here on cathodoluminescence of α-quartz after 175 keV Rb-ion implantation and epitaxial growth when annealing the samples in air or 18 O 2. In the cathodoluminescence spectra taken at room temperature, five bands were identified. In addition to three intrinsic bands at 2.40, 2.79, and 4.30 eV, which are related to the quartz and/or silica matrix, two strong violet sub-bands at 3.25 and 3.65 eV were observed, which appear to be strongly correlated with the presence of alkali ions and/or the degree of epitaxy of the matrix. Their properties and origin are discussed in relation to similar bands observed after Ba, Ge, and Na ion implantation.