spinel vs spinel ruby

spinel and spinel ruby both are nouns.

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

As nouns, spinel ruby is a hyponym of spinel; that is, spinel ruby is a word with a more specific, narrower meaning than spinel:

spinel: a hard glassy mineral consisting of an oxide of magnesium and aluminum; occurs in various colors that are used as gemstones
spinel ruby: a spinel used as a gemstone (usually dark red)

Other hyponyms of spinel include ruby spinel, ceylonite, pleonaste.

spinel (noun)	spinel ruby (noun)
a hard glassy mineral consisting of an oxide of magnesium and aluminum; occurs in various colors that are used as gemstones	a spinel used as a gemstone (usually dark red)