I've seen a couple of wild ones in X (Rock Smash), but it says it is only found in Y.
Nope Binacle is available in both Pokémon X and Y and can be found in the exact same locations in both games by using Rock Smash to smash rocks:
Route 8, Route 12, Ambrette Town, Cyllage City and Azure Bay.
Source: http://bulbapedia.bulbagarden.net/wiki/Binacle
Hope I helped :)