I believe that, yes. Yes they do. At nano scale the shape of the nano particle determines it's reflective colors. Gold turns to red at nano scale. Look at old cathedral windows. The red panes are made from gold. It's not just a matter of reflection , there is also absorbtion and refraction. question: does air have a color or does it have refractive properties? Witness a rainbow. Do hydrogen and oxygen have colors? Yet when light shines through it is refracted into it's componenet color wavelengths. Have to have light to what we perceive as color. Please Register or Log in to view the hidden image! No EM waves, no color.