Having a play of lustrous rainbow colors:
— A milky opalescent (or opaline) luster.

synonyms: iridescent, nacreous, opalescent, pearlescent.

Roget 440: variegated etc. v.; many-colored, many-hued; divers-colored, party-colored; dichromatic, polychromatic; bicolor^†, tricolor, versicolor^†; of all the colors of the rainbow, of all manner of colors; kaleidoscopic.    iridescent; opaline^†, opalescent; prismatic, nacreous, pearly, shot, gorge de pigeon, chatoyant^†; irisated^†, pavonine^†.    pied, piebald; motley; mottled, marbled; pepper and salt, paned, dappled, clouded, cymophanous^†.    mosaic, tesselated, plaid; tortoise shell etc. n.. spotted, spotty; punctated^†, powdered; speckled etc. v.; freckled, flea-bitten, studded; flecked, fleckered^†; striated, barred, veined; brinded^†, brindled; tabby; watered; grizzled; listed; embroidered etc. v.; daedal^†; naevose^†, stipiform^†; strigose^†, striolate^†.    (iii) PERCEPTIONS OF LIGHT ... show more

Roget 427: semitransparent, translucent, semipellucid^†, semidiaphanous^†, semiopacous^†, semiopaque; opalescent, opaline^†; pearly, milky; frosted, nacreous.   

Polish: opalowy