Gray or Grey

Ever wonder about this? Do I have gray highlights in my hair or is it actually grey? Maybe there were really 65 crayolas in the box but we were confused by the gre(a)y dibacle? Ray or rey doesn't seem to be an issue so we add the 'g' to it and it all breaks loose. That's all I have today, hope to solve this mystery soon or I may have to chave my head to avoid the gre(a)y issue later in life.