nacreous vs iridescent

nacreous and iridescent both are adjectives.

Word	Noun	Adjective	Verb	Adverb
nacreous	No	Yes	No	No
iridescent	No	Yes	No	No

As adjectives, nacreous and iridescent are synonyms defined as:

Other synonyms of nacreous include opalescent, opaline, pearlescent.

nacreous (adjective)	iridescent (adjective)
consisting of or resembling mother-of-pearl	having a play of lustrous rainbow colors
having a play of lustrous rainbow colors	varying in color when seen in different lights or from different angles