shale vs humic shale

shale and humic shale both are nouns.

Word	Noun	Adjective	Verb	Adverb
shale	Yes	No	No	No
humic shale	Yes	No	No	No

As nouns, humic shale is a hyponym of shale; that is, humic shale is a word with a more specific, narrower meaning than shale:

shale: a sedimentary rock formed by the deposition of successive layers of clay
humic shale: shale that is rich in humic acids

Other hyponyms of shale include oil shale.

shale (noun)	humic shale (noun)
a sedimentary rock formed by the deposition of successive layers of clay	shale that is rich in humic acids