blue copperas vs blue stone

blue copperas and blue stone both are nouns.

Word	Noun	Adjective	Verb	Adverb
blue copperas	Yes	No	No	No
blue stone	Yes	No	No	No

As nouns, blue copperas and blue stone are synonyms defined as:

blue copperas and blue stone: hydrated blue crystalline form of copper sulfate

Other synonyms of blue copperas include blue vitriol, chalcanthite.

blue copperas (noun)	blue stone (noun)
hydrated blue crystalline form of copper sulfate	hydrated blue crystalline form of copper sulfate