iridescence vs opalescence

iridescence and opalescence both are nouns.

Word	Noun	Adjective	Verb	Adverb
iridescence	Yes	No	No	No
opalescence	Yes	No	No	No

As nouns, iridescence and opalescence are synonyms defined as:

iridescence and opalescence: the visual property of something having a milky brightness and a play of colors from the surface

iridescence (noun)	opalescence (noun)
the visual property of something having a milky brightness and a play of colors from the surface	the visual property of something having a milky brightness and a play of colors from the surface