ruby spinel vs spinel

ruby spinel and spinel both are nouns.

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

As nouns, spinel is a hypernym of ruby spinel; that is, spinel is a word with a broader meaning than ruby spinel:

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

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