jadestone vs opaque gem

jadestone and opaque gem both are nouns.

Word	Noun	Adjective	Verb	Adverb
jadestone	Yes	No	No	No
opaque gem	Yes	No	No	No

As nouns, opaque gem is a hypernym of jadestone; that is, opaque gem is a word with a broader meaning than jadestone:

jadestone: a semiprecious gemstone that takes a high polish; is usually green but sometimes whitish; consists of jadeite or nephrite
opaque gem: a gemstone that is opaque

jadestone (noun)	opaque gem (noun)
a semiprecious gemstone that takes a high polish; is usually green but sometimes whitish; consists of jadeite or nephrite	a gemstone that is opaque