Depends on how much space you want to lose, but you also have to make sure you maintain the fire-rating of the wall assembly with whatever you do. You'll need at least one layer of 5/8 Type X drywall for one-hour fire resistance, you may need two by code. Obviously, more drywall will create more mass, and more sound dampening.

You can also hang the rock on resilient channel (RC-1 channel), which will help further- but you have to make sure the assembly is fire-rated. You'll also lose around 1/2" with the channels.

Or, you can create a staggered stud wall and weave sound batts thru that, followed by the channels and drywall- you'll lose a few inches doing that though.