stone-gray vs stone-grey

stone-gray and stone-grey both are adjectives.

Word	Noun	Adjective	Verb	Adverb
stone-gray	No	Yes	No	No
stone-grey	No	Yes	No	No

As adjectives, stone-gray and stone-grey are synonyms defined as:

Other synonyms of stone-gray include slate-gray, slate-grey, slatey, slaty-gray, slaty-grey, slaty.

stone-gray (adjective)	stone-grey (adjective)
of the color of slate or granite	of the color of slate or granite