The invention relates to composite materials having an optical effect, comprising at least one moulding which essentially consists of core/shell particles whose shell forms a matrix and whose core is essentially solid and has an essentially monodisperse size distribution, where a difference exists between the refractive indices of the core material and of the shell material, and at least one further material which determines the mechanical properties of the composite, and to a process for the production of the composite materials. The materials according to the invention exhibit a viewing angle-dependent colour effect with freely adjustable mechanical properties.