ebony vs pitch black

ebony and pitch black both are nouns.

Word	Noun	Adjective	Verb	Adverb
ebony	Yes	Yes	No	No
pitch black	Yes	No	No	No

As nouns, ebony and pitch black are synonyms defined as:

Other synonyms of ebony include coal black, jet black, sable, soot black.

ebony (noun)	pitch black (noun)
a very dark black	a very dark black
tropical tree of southern Asia having hard dark-colored heartwood used in cabinetwork
hard dark-colored heartwood of the ebony tree; used in cabinetwork and for piano keys

ebony (adjective)	pitch black (adjective)
of a very dark black