earth color vs ocher

earth color and ocher both are nouns.

Word	Noun	Adjective	Verb	Adverb
earth color	Yes	No	No	No
ocher	Yes	Yes	No	No

As nouns, ocher is a hyponym of earth color; that is, ocher is a word with a more specific, narrower meaning than earth color:

earth color: a colored mineral used as a pigment
ocher: any of various earths containing silica and alumina and ferric oxide; used as a pigment

Other hyponyms of earth color include sienna, ochre, umber.

earth color (noun)	ocher (noun)
a colored mineral used as a pigment	a moderate yellow-orange to orange color
	any of various earths containing silica and alumina and ferric oxide; used as a pigment

earth color (adjective)	ocher (adjective)
	of a moderate orange-yellow color