bone black vs animal charcoal

bone black and animal charcoal both are nouns.

Word	Noun	Adjective	Verb	Adverb
bone black	Yes	No	No	No
animal charcoal	Yes	No	No	No

As nouns, bone black and animal charcoal are synonyms defined as:

bone black and animal charcoal: black substance containing char in the form of carbonized bone; used as a black pigment

Other synonyms of bone black include animal black, bone char.

bone black (noun)	animal charcoal (noun)
black substance containing char in the form of carbonized bone; used as a black pigment	black substance containing char in the form of carbonized bone; used as a black pigment