opalescent
1. [ adjective ] (color) having a play of lustrous rainbow-like colors
Synonyms: nacreous opaline pearlescent iridescent
Examples:

"an iridescent oil slick" "nacreous (or pearlescent) clouds looking like mother-of-pearl" "a milky opalescent (or opaline) luster"

Related terms: bright
Similar spelling:   opalesce
  opalescence
  opalise