The type of rock that forms most often near an active volcano is igneous rock.

Here's why:

* Volcanic Eruptions: Active volcanoes erupt molten rock called magma. When magma reaches the Earth's surface, it's called lava.

* Cooling and Solidification: As lava cools and solidifies, it forms igneous rocks.

* Types of Igneous Rocks: The specific type of igneous rock depends on the composition of the lava and how it cools. Common types near volcanoes include:

* Extrusive Igneous Rocks: These form from lava that cools quickly on the Earth's surface, like basalt, rhyolite, and andesite.

* Intrusive Igneous Rocks: These form from magma that cools slowly underground, like granite and gabbro.

So, while other types of rocks can be found near volcanoes (like sedimentary rocks from erosion), igneous rocks are the most common type formed directly by volcanic activity.