a clear to white liquid secreted by sea hares (genus Aplysia) that becomes viscous upon contact with water
having a play of lustrous rainbow colors
"an iridescent oil slick"
"nacreous (or pearlescent) clouds looking like mother-of-pearl"
"a milky opalescent (or opaline) luster"
resembling opal in its iridescence; having a milky white iridescence.