The replacement of single-crystal compounds by polycrystalline compounds in some magneto-optical devices is proposed. For this purpose a characterized polycrystalline, Cd(0.55)Mn(0.45) Te, has been manufactured. Its Verdet constant and cutoff wavelength are identical to those of single crystals of the same composition. Optical transmission is lower in polycrystals because they have larger light-scattering coefficients; hence they are not well suited for applications such as isolators but are adequate for magnetometers, modulators, and similar devices.