The Haunted Card (only gimmick)

The magician asks a spectator to choose a card; it is put back in the deck and this is placed on the table. The spectator is then asked to rest his finger on the top of the deck. Suddenly, right under his finger a "magical force" separates the deck into two... exactly where the chosen card is!

• The magic happens in the hands of the spectators.
• Only the gimmick necessary for the effect is supplied. 
• The effect is easy to perform, can be done with any card, and is immediately repeatable.