Mountains formed by geothermal pressure or material discharge are called volcanic mountains.

Here's how it works:

* Geothermal pressure: Heat from the Earth's interior melts rock, creating magma. This magma is less dense than the surrounding rock and rises, creating pressure.

* Material discharge: The magma eventually erupts onto the Earth's surface as lava, ash, and gases. Over time, these materials build up, creating a cone-shaped mountain.

Examples of volcanic mountains:

* Mount Fuji (Japan)

* Mount Vesuvius (Italy)

* Mount Kilimanjaro (Tanzania)

* Mauna Kea (Hawaii)

It's important to note that not all mountains are volcanic. Some are formed by tectonic plate collisions (like the Himalayas) or erosion (like the Appalachian Mountains).