Andesite has between about 52 and 63 weight percent silica (SiO2). It contains crystals composed primarily of plagioclase feldspar and one or more of the minerals pyroxene (clinopyroxene and orthopyroxene) and lesser amounts of hornblende. At the lower end of the silica range, andesite lava may also contain olivine. Andesite magma commonly erupts from stratovolcanoes as thick lava flows, some reaching several kilometres in length. Andesite magma can also generate strong explosive eruptions to form pyroclastic flows and surges and enormous eruption columns. Andesites erupt at temperatures between 900 and 1100 °C.
- USGS Photo Glossary
- Snelling, Andrew, Radioisotope Case Studies, chapter 8 of DeYoung, Don, "Thousands ... Not Billions", Master Books, 2005 ISBN 0-89051-441-0
- Snelling, 2005, p. 125