Optical effects due to electric dipole–magnetic dipole interference were predicted for crystals which are noninvariant under space-inversion and time-reversal symmetry. We report measurements of the nonreciprocal rotation and ellipticity of light reflected from antiferromagnetic-magnetoelectric Cr 2O3 in a spectral range from 1.6 to 2.5 eV, which comprises A2 ! 2E, T1, and T2 transitions. An analysis provides new information about symmetries of excited states and shows that previous assignments of excitonic lines cannot be entirely reconciled with our data. [S0031-9007(96)00330-4]