About to move into a new house and have an odd set up. I have a stone fireplace, but was able to get the builder to fill in the back side with wood 2x4 so that I couldn't miss a stud. I plan to purchase both a Ultra-Slim Adjustable Tilting Wall Mount Bracket from Monoprice, but wanted to see what you pros recommend for hardware to go through the stone and into the 2x4s?
Use long wood lags, drill through the stone with a masonry bit larger than the lag, then use a wood bit to drill the rest of the the standard pre drill size for the lag, the stone provides no structural support at all. It would have been easier to have your contractor place a 2x12 in the middle of where the stone is for you to mount the TV onto than all that blocking behind the wall.