pearl grey vs pearl gray

pearl grey and pearl gray both are adjectives.

Word	Noun	Adjective	Verb	Adverb
pearl grey	No	Yes	No	No
pearl gray	No	Yes	No	No

As adjectives, pearl grey and pearl gray are synonyms defined as:

pearl grey (adjective)	pearl gray (adjective)
of a grey with a pearly tinge	of a grey with a pearly tinge