Rocks formed by fire, meaning those formed from molten or partially molten material, are called igneous rocks.

Here's a breakdown:

* Igneous comes from the Latin word "ignis", meaning "fire".

* Magma is molten rock found beneath the Earth's surface.

* Lava is molten rock that has erupted onto the Earth's surface.

Igneous rocks are classified based on their mineral composition and texture, which are influenced by the cooling and crystallization process.