Andesite most commonly denotes fine-grained, usually porphyritic rocks; in composition these correspond roughly to the intrusive igneous rock diorite and consist essentially of andesine (a plagioclase feldspar) and one or more ferromagnesian minerals, such as pyroxene or biotite.

Do andesite and basalt have the same composition?

Andesite is the name of a family of fine-grained, extrusive igneous rocks that are usually light to dark gray in color. They have a mineral composition that is intermediate between granite and basalt.

Do andesite and diorite have the same composition?

Diorite and andesite are similar rocks. They have the same mineral composition and occur in the same geographic areas. ... Andesite forms when a similar magma crystallizes quickly at Earth's surface. That rapid cooling produces a rock with small crystals.