Here's why:

* Formation: Scoria forms when lava with a high gas content erupts, and the gas bubbles get trapped within the solidifying rock.

* Appearance: Scoria is characterized by its dark color (usually reddish-brown to black) and its numerous, often irregular holes (vesicles) that give it a spongy appearance.

* Common Occurrence: Scoria is a common volcanic rock found in volcanic fields and near volcanoes.

Other vesicular rocks include:

* Pumice: Pumice is lighter and more porous than scoria, and it can float on water.

* Tuff: Tuff is a volcanic rock formed from the accumulation of volcanic ash, and it can sometimes be vesicular depending on the type of ash.

Let me know if you would like to learn more about any of these vesicular rocks!