I remembered that shininess of a material is because of reflection, ie surface current responding to light. Mathematically, one can solve Maxwell equations under a relevant boundary condition, with plane waves ansatz. This math only corresponds to situations when the size of the metal surface is way larger than the wavelength of light. What happen if the surfaces are smaller than wavelength of say ~600nm light?
What happen for metals that have domains size less than the wavelength? What happen for small graphene sheets whose edges are passivated by hydrogen, and are shorter than the wavelength? If electrons cannot move across different domains that are shorter than the wavelength, can the material possibly be shiny?