Andesite

Type	Igneous Rock
Texture	Aphanitic (Fine-grained)
Origin	Extrusive/Volcanic
Chemical Composition	Intermediate
Color	Medium Gray
Mineral Composition	Sodium – Calcium Plagioclase, Hornblende, Biotite
Tectonic Environment	Convergent Boundary – both Island Arc-type and Andean-type subduction zones