emerald vs greenness

emerald and greenness both are nouns.

Word	Noun	Adjective	Verb	Adverb
emerald	Yes	No	No	No
greenness	Yes	No	No	No

As nouns, greenness is a hypernym of emerald; that is, greenness is a word with a broader meaning than emerald:

Other hypernyms of emerald include green, viridity.

emerald (noun)	greenness (noun)
the green color of an emerald	green color or pigment; resembling the color of growing grass
a transparent piece of emerald that has been cut and polished and is valued as a precious gem	the lush appearance of flourishing vegetation
a green transparent form of beryl; highly valued as a gemstone	the state of not being ripe