ruby spinel vs spinel ruby

ruby spinel and spinel ruby both are nouns.

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

As nouns, ruby spinel and spinel ruby are synonyms defined as:

ruby spinel and spinel ruby: a spinel used as a gemstone (usually dark red)

ruby spinel (noun)	spinel ruby (noun)
a spinel used as a gemstone (usually dark red)	a spinel used as a gemstone (usually dark red)