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The axial circular-dichroism spectrum of a synthetic amethyst crystal has been studied for the first time. Bands both of the positive and negative signs are revealed. New information on the color centers of amethyst and their electronic structure is obtained.

The vibrational spectra of crystals of bismuth borates Bi24B2O39, Bi4B2O9, BiBO3, and Bi2B8O15 were obtained for the first time, and the spectra of Bi3B5O12 and BiB3O6 crystals measured in the range 30–1600 cm−1 at room temperature were refined. The lines observed were assigned to the corresponding vibrational transitions on the basis of the theoretical group analysis and comparison of the obtained results with the vibrational spectra of borates of different composition. The complication of the structure of bismuth borates with increasing content of B2O3 was traced by the example of vibrational spectra.

Absorption and circular-dichroism spectra of iron-doped AlPO4 crystals have been studied. For the first time, the experimental data on the electronic states of the [FeO4]5− complex are obtained in the range from 190 to 350 nm with due regard for the interactions that cannot be described within the one-electron approximation. The bands observed in the absorption and circular-dichroism spectra are attributed to corresponding electronic transitions. The advantages of the use of crystal-field-induced circular dichroism in comparison with other spectroscopic methods in the analysis of the electronic states of impurity ions in gyrotropic crystalline matrices are considered on the [FeO4]5− complex.

The Raman spectra of Bi24AlPO40 and Bi38ZnO58 crystals have been studied for the first time. The polarization Raman spectra of Bi12GeO20, Bi12TiO20, Bi24AlPO40, and Bi38ZnO58 crystals are also studied. The lines in the Raman spectra of Bi12TiO20, Bi24AlPO40, and Bi38ZnO58 are identified and compared with the lines of the Bi12GeO20 spectra studied earlier. It is shown that the differences in the Raman spectra of the crystals studied are associated with the specific features of their atomic structures.

The experimental data on the optical and chiro-optical properties of crystals with the sillenite structure Bi12MxO20 ± δ (M= elements of II–VIII groups) have been reviewed. The relations between the changes in the chemical composition, the crystal structure of Bi12MxO20 ± δ compounds, absorption, circular dichroism, and optical rotation spectra of sillenites have been established. A model taking into account the contribution of the electronic transitions of optically active tetrahedral [MO4]n− complexes to the total optical rotation in sillenites is suggested. The data on the state (oxidation degree) and the recharging processes of 3d-elements in sillenites are systematized. The models of optical centers responsible for the photochromic effect in sillenites are critically analyzed.