Andesite is an aphanitic (fine-grained) to porphyritic (coarse-grained) igneous rock that is intermediate in its content of silica and low in alkali metals. It has less than 20% quartz and 10% feldspathoid by …

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. …

Jul 3, 2023 · Andesite is a fine-grained, intermediate volcanic or extrusive igneous rock. Its composition lies between basalt and dacite, and it has mainly sodium-rich plagioclase and one or more mafic …

Apr 11, 2018 · Andesite is volcanic rock named after the Andes Mountains. Intermediate in silica content, it is usually gray in color and may be fine-grained or porphyritic. Andesite is the volcanic …

Andesite is a gray to black volcanic rock with between about 52 and 63 weight percent silica (SiO2). Andesites contain crystals composed primarily of plagioclase feldspar and one or more of the …

andesite, any member of a large family of rocks that occur in most of the world’s volcanic areas. Andesites occur mainly as surface deposits and, to a lesser extent, as dikes and small plugs.

Andesite commonly erupts from stratovolcanoes, where they form small-volume flows that typically advance only short distances down the flanks of a volcano. The two examples shown here are short …

The meaning of ANDESITE is an extrusive usually dark grayish rock consisting essentially of oligoclase or feldspar.

Mar 28, 2024 · Andesite is a hard, moderately dense rock with typical densities of 2.4-2.8g/cm 3 and a Mohs hardness scale of 6-7. Its color is usually light to medium gray on a fresh surface. However, …

The term Andesite was used for the first time by Leopold von Buch in 1835 to describe a group of rocks found in the Andes of Bolivia and Chile and also in the Kamchatka in Russia.