How fast things bounce back when they collide depends on their elasticity. Elasticity describes how well something goes back to its original shape after the forces acting on it is released. For example, when you press a spring on its both sides, you change its shape (make it shorter). But after you release your hands, it will go back to its original length. Thus, we say springs are elastic.
Elastic stuff doesn't have to be "soft." In fact, a lot of hard things are elastic under normal amount of force. When you press a marble, it becomes slightly smaller (although the change is too tiny to see), but will come back to its original size when the force is released.
When a marble hits a ceramic tile, they both change shapes because of the force they exert on each other. Since they are both somewhat elastic, they want to go back to their original shapes, and generate forces to push them apart. This is similar to the repelling force you feel when you press a spring. As a result, the marble bounces back from the ceramic tile.
(published on 03/03/2012)