sapphire vs blueness

sapphire and blueness both are nouns.

Word	Noun	Adjective	Verb	Adverb
sapphire	Yes	Yes	No	No
blueness	Yes	No	No	No

As nouns, blueness is a hypernym of sapphire; that is, blueness is a word with a broader meaning than sapphire:

sapphire: a light shade of blue
blueness: blue color or pigment; resembling the color of the clear sky in the daytime

Other hypernyms of sapphire include blue.

sapphire (noun)	blueness (noun)
a light shade of blue	blue color or pigment; resembling the color of the clear sky in the daytime
a transparent piece of sapphire that has been cut and polished and is valued as a precious gem
a precious transparent stone of rich blue corundum valued as a gemstone

sapphire (adjective)	blueness (adjective)
of something having the color of a blue sapphire