firestone vs sandstone

firestone and sandstone both are nouns.

Word	Noun	Adjective	Verb	Adverb
firestone	Yes	No	No	No
sandstone	Yes	No	No	No

As nouns, sandstone is a hypernym of firestone; that is, sandstone is a word with a broader meaning than firestone:

firestone: a sandstone that withstands intense heat; used to line fireplaces and furnaces and kilns
sandstone: a sedimentary rock consisting of sand consolidated with some cement (clay or quartz etc.)

firestone (noun)	sandstone (noun)
a sandstone that withstands intense heat; used to line fireplaces and furnaces and kilns	a sedimentary rock consisting of sand consolidated with some cement (clay or quartz etc.)
a piece of flint that is struck to light a fire