Why is Gray spelled Gray and Grey?

I ask for two reasons...

1. Cause Kiki thought it would be a great blog topic (she was right)

2. Cause I am often spellchecking my outgoing emails and I get told "Gray" is "Grey" by my iPhone way to much... really chaps my hide.

To solve this conundrum I Googled...and basically my answer was this

" Grey and gray are both acceptable spellings of the word. "gray" is the American adaptation of "grey", kinda like "color" is the American adaptation of "colour".... Wow BORING but INFORMATIVE

Speaking of gray, over at KM Inc. We are doing a gray master bedroom which is gonna be amazing!
I'll post some photos of the "after" once we get there!

we gave our client two options: a "his" and "her" both with a gray color scheme