DIY painted rock fireplace. I updated our rock fireplace last weekend.  It was 70's brown stone and I wanted to lighten it up to better match our walls, which we were painting grey.  It only took about 2 hours and less than $15 to do.  I made a simple mix of  grey acrylic paint (found at Michaels for .75 ea. (took 3 bottles total) and a little water.  Sponged it over the brick (left mortar dark grey) and sealed it with a $10 gallon of masonry seal (found at home depot).
{}