ruby vs chromatic

ruby is a noun but chromatic is not a noun.

Word	Noun	Adjective	Verb	Adverb
ruby	Yes	Yes	No	No
chromatic	No	Yes	No	No

ruby (noun)	chromatic (noun)
a deep and vivid red color
a transparent piece of ruby that has been cut and polished and is valued as a precious gem
a transparent deep red variety of corundum; used as a gemstone and in lasers

ruby (adjective)	chromatic (adjective)
of a color at the end of the color spectrum (next to orange); resembling the color of blood or cherries or tomatoes or rubies	being or having or characterized by hue
	based on a scale consisting of 12 semitones
	able to refract light without spectral color separation