Igneous rocks that form when melted rock cools on the surface of Earth are called extrusive igneous rocks.

Here's why:

* Extrusive refers to the process of eruption or being expelled from the Earth's interior.

* Igneous refers to rocks formed from the cooling and solidification of magma or lava.

Some examples of extrusive igneous rocks include:

* Basalt: A dark-colored, fine-grained rock that is common in volcanic areas.

* Rhyolite: A light-colored, fine-grained rock that is rich in silica.

* Andesite: A medium-colored, fine-grained rock that is intermediate in composition between basalt and rhyolite.

* Obsidian: A dark, glassy rock that forms when lava cools rapidly.

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