regalia vs crown jewels

regalia and crown jewels both are nouns.

Word	Noun	Adjective	Verb	Adverb
regalia	Yes	No	No	No
crown jewels	Yes	No	No	No

As nouns, crown jewels is a hyponym of regalia; that is, crown jewels is a word with a more specific, narrower meaning than regalia:

regalia: paraphernalia indicative of royalty (or other high office)
crown jewels: regalia (jewelry and other paraphernalia) worn by a sovereign on state occasions

regalia (noun)	crown jewels (noun)
paraphernalia indicative of royalty (or other high office)	regalia (jewelry and other paraphernalia) worn by a sovereign on state occasions
especially fine or decorative clothing