Opalescent means colourless or white like an opal, or changing colour like an opal. Elaine turned her opalescent eyes on him. a sky which was still faintly opalescent. + opalescence opal·es·cence The sunset was making great splashes of fiery opalescence across the sky. having colours that shine and seem to change
having a play of lustrous rainbow-like colors; "an iridescent oil slick"; "nacreous (or pearlescent) clouds looking like mother-of-pearl"; "a milky opalescent (or opaline) luster"
Reflecting a milky or pearly light from the interior; having an opaline play of colors
the milky iridescent appearance of a dense transparent medium when it is illuminated by polychromatic visible radiation (such as sunlight) due to local fluctuations in its density and therefore in its refractive index