Abstract: A photonic crystal material comprises an ordered array of nanoscopic particles locked into position by a dehydrated hydrogel matrix. The material can be powdered and used as a colorant. The photonic crystal material has the advantage that its array of nanoscopic particles self assembles for ease in producing a diffractive material that retains these properties when added to other polymers and binders. This material may be added to polymers with ionic content without destroying the array that produces diffraction. The material is easily stored compared to hydrated hydrogels that must be stored in water.