andesite

[ an-duh-zahyt ]

noun

1. a dark-colored volcanic rock composed essentially of plagioclase feldspar and one or more mafic minerals, as hornblende or biotite.

andesite

/ ˈændɪˌzaɪt /

noun

1. a fine-grained tan or grey volcanic rock consisting of plagioclase feldspar, esp andesine, amphibole, and pyroxene

andesite

/ ăn′dĭ-zīt′ /

1. A gray, fine-grained volcanic rock. Andesite consists mainly of sodium-rich plagioclase feldspar and one or more mafic minerals such as biotite, hornblende, or pyroxene. It often contains small, visible crystals (phenocrysts) of plagioclase.

Other Words From

• an·de·sit·ic [an-d, uh, -, zit, -ik], adjective

Word History and Origins

Origin of andesite¹

1840–50; named after Andes; -ite ¹

Word History and Origins

Origin of andesite¹

C19: from Andes + -ite ¹

Example Sentences

In the same flow hypersthene-andesite may occur in one portion, while in close proximity the lava is an augite-andesite.

From Project Gutenberg

It also surrounds olivine in this same rock, which is a hypersthene-andesite, the hornblende and olivine being only accessory.

From Project Gutenberg

On Crater Peak, and below on Gibraltar, hypersthene andesite occurs with considerable variation of color and texture.

From Project Gutenberg

The rocks thus extruded are mainly composed of dark, heavy basic material, such as basalt and andesite.

From Project Gutenberg

In the Breidden district are the barren Criggeon shales with ashes and flows of andesite.

From Project Gutenberg