Mountains formed by the eruption of magma on Earth's surface are called volcanic mountains or stratovolcanoes.

Here's a breakdown:

* Volcanic Mountains: These mountains are formed by the accumulation of lava, ash, and other volcanic materials over time.

* Stratovolcanoes: These are tall, conical volcanoes with steep slopes, built up by layers of lava flows, ash, and other volcanic debris.

Here are some famous examples of volcanic mountains:

* Mount Fuji (Japan)

* Mount Vesuvius (Italy)

* Mount Kilimanjaro (Tanzania)

* Mount Etna (Italy)

* Mount Rainier (USA)

Let me know if you'd like to learn more about any specific volcanic mountain!