This rock has a very similar composition to that of basalt, with calcic-plagioclase feldspar and pyroxene being the essential minerals. Olivine and magnetite are also usually present in vesicular basalt.

TEXTURE The rock is riddled with empty gas-bubble cavities called vesicles. The matrix is fine grained, often porphyritic. If the cavities are infilled with minerals, vesicular basalt becomes an amygdaloidal basalt.

ORIGIN Forms from the cooling of basaltic lava.

Group: IGNEOUS

Origin: Extrusive

Grain size: Fine

Crystal shape: Anhedral, Euhedral

Classification: Mafic

Occurrence: Volcano

Color: Dark