spinel vs pleonaste

spinel and pleonaste both are nouns.

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

As nouns, pleonaste is a hyponym of spinel; that is, pleonaste 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
pleonaste: a dark-colored spinel containing iron

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

spinel (noun)	pleonaste (noun)
a hard glassy mineral consisting of an oxide of magnesium and aluminum; occurs in various colors that are used as gemstones	a dark-colored spinel containing iron