Andesite is an extrusive igneous rock consisting primarily of plagioclase feldspars plus pyroxene and/or hornblende. Biotite, magnetite, quartz and sphene are common constituents.

Andesite has the equivalent composition to the plutonic igneous rock, diorite.

Andesite is named after the Andes mountain range. These rocks are found near the subduction zones of ocean tectonic plates, along continental margins.

See Steve's video interview about asteroid capture at Moonandback:
Part 1
Part 2
Part 3

Copyright ©1995-2023 by Amethyst Galleries, Inc.