chalcedony vs transparent gem

chalcedony and transparent gem both are nouns.

Word	Noun	Adjective	Verb	Adverb
chalcedony	Yes	No	No	No
transparent gem	Yes	No	No	No

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

chalcedony: a milky or greyish translucent to transparent quartz
transparent gem: a gemstone having the property of transmitting light without serious diffusion

Other hypernyms of chalcedony include quartz.

chalcedony (noun)	transparent gem (noun)
a milky or greyish translucent to transparent quartz	a gemstone having the property of transmitting light without serious diffusion