Using 3/8" thin Gypsum board for fireplace wall?

Hey all,

I have a wood fireplace in the corner of the living room with a wall from floor to ceiling. The fireplace wall had this 1" or so thick brick on it.. the wall looked like a backdrop to an 1980's stand-up comic show.

I took down the wall and noticed that the builders used regular 1/2" gypsum board and not fireboard/cementboard or anything like that.

I then read that all drywall is extrememly heat and fire resistent.

I would like put some new drywall up in it's place. I will be using this wall as a backer for putting up some stone vaneer. It is desireable for me to have the wall being very thin.

Is 3/8" Gypsum a good idea for this purpose? Any other thin alternatives?

Thanks,