When we talk of Rock Balancing or Stone Balancing we mean to put one or more rocks in a state of equilibrium where the rock's contact point is kept very small. This sculptures appear often physically impossible while actually being only highly improbable. It's often mistaken with rock piling which in my opinion is not quite the same thing even such piles are also somewhat balanced, yet they usually touch each other on multiple contact points which are widely spread over the surface of the rocks.

The art of rock balancing, finding stillness through gravity

Khan Academy