We started to remove the sealer but I am pretty sure they glued it to the existing subway tile 
How do I remove a 4” granite backsplash from a subway tiled wall?
by
Laurie
Laurie....are you replacing your counter top as well? Or are you removing the subway tile. It will be very hard to get behind that granite with out chipping the tile. Granite is one of the hardest kitchen surfaces and why it is still so popular.
It more likely was glued on. Trying to pry it off may crack it, breaking the tile, or the tile may come off with it.