Stoneclip  has discussed a particular case in Bellbowrie Community where stone panels were used.

The stone panels in this case are 600x300 x 30 mm down to 300 mm x 300mm x30 mm.

The stone size comes in at 75 kgs/m2 when it is dry, so it does not stand a chance of staying in place with tile fix as was used in this case and to top it off the fixer did not put on enough glue and as well he has put it on and it has gone dry with a crust before the panel was adhered to it.