Incident light enters a faceted gemstone and is routed along optical paths to exit the gemstone as emergent light. At least one diffraction grating is patterned on the gemstone in an asymmetrical manner relative to an axis of symmetry. The diffraction grating has a diffractive structure positioned on at least one facet for diffracting the light being routed along at least one of the optical paths to enhance color dispersion of the emergent light. The diffraction grating is the only diffraction grating to diffract the light being routed along the at least one optical path to diminish haze of the emergent light.