An exchangeable component of a textile machine with a surface coating or a treated surface within which color elements are embedded is provided. The color elements in the surrounding area of the coating or the treatment, upon radiation by a light of a first wave length or of a first spectral range of wave lengths, emit a light of a second predetermined wave length or a second predetermined spectral range of wave lengths. Furthermore, a detection apparatus is provided with a source of illumination for the radiation of such a component and for the detection of the emitted light.