ultramarine blue vs ultramarine

ultramarine blue and ultramarine both are nouns.

Word	Noun	Adjective	Verb	Adverb
ultramarine blue	Yes	No	No	No
ultramarine	Yes	Yes	No	No

As nouns, ultramarine blue and ultramarine are synonyms defined as:

ultramarine blue and ultramarine: blue pigment made of powdered lapis lazuli

ultramarine blue (noun)	ultramarine (noun)
blue pigment made of powdered lapis lazuli	a vivid blue to purple-blue color
	blue pigment made of powdered lapis lazuli

ultramarine blue (adjective)	ultramarine (adjective)
	of a brilliant pure blue to purplish blue color