fire opal vs opal

fire opal and opal both are nouns.

Word	Noun	Adjective	Verb	Adverb
fire opal	Yes	No	No	No
opal	Yes	No	No	No

As nouns, opal is a hypernym of fire opal; that is, opal is a word with a broader meaning than fire opal:

fire opal: an opal with flaming orange and yellow and red colors
opal: a translucent mineral consisting of hydrated silica of variable color; some varieties are used as gemstones

fire opal (noun)	opal (noun)
an opal with flaming orange and yellow and red colors	a translucent mineral consisting of hydrated silica of variable color; some varieties are used as gemstones