Spectroscopic studies of Cr3+ ions in natural single crystal of magnesium aluminate spinel MgAl2O4. - Mironova-Ulmane, N.; Brik, M.G.; Grube, J.; Krieke, G.; Antuzevics, A.; Skvortsova, V.; Kemere, M.; Elsts, E.; Sarakovskis, A.; Piasecki, M.; Popov, A.I. (Optical Materials, 2021)