They are formed when the erupted magma or lava, cool and sollidifies below or above the earths surface respectively.
Extrusive igneous rocks
Magma that is ejected during a volcanic eruption forms extrusive igneous rocks. They are also referred to as volcanic rocks.
When igneous rocks from a volcanic eruption cools it forms Crystalline Rocks.
Rocks formed from volcanic eruptions are called igneous rocks. These rocks form when magma or lava cools and solidifies, either beneath the Earth's surface (intrusive) or at the surface (extrusive). Examples include basalt, rhyolite, and pumice.
They were formed by the volcanic eruption
Pyroclasts are rock fragments or rocks formed from volcanic fragments thrown into the air as a result of a volcanic eruption. Also known as tephra, some examples of these rocks include pumice, reticulite and scoria.
When Mount Vesuvius erupted, it produced igneous rocks such as basalt, andesite, and dacite due to the volcanic activity. These rocks are created from the cooling and solidification of molten magma. Additionally, the eruption may have also produced pyroclastic rocks such as pumice and volcanic ash.
The rocks found near Krakatau are primarily volcanic in origin, such as basalt, andesite, and dacite. These rocks were formed during the explosive eruption of Krakatau in 1883 and subsequent volcanic activity in the region. Additionally, pumice rocks, a type of volcanic glass, can also be found in the area due to the explosive nature of the eruption.
Surtsey
Many extrusive volcanic rocks contain holes, or vesicles, which have formed from gases trapped in the magma during eruption. As the lava cools and solidifies, these gases escape, leaving behind the characteristic holes in the rock.
It wasn't it was the big bang
Igneous Rock is formed when a volcano erupts and the the lava cools down to harden. Pumice Stone Extrusive Rocks Glass Rocks Hope this Helps :)