A fine-grained igneous rock composed of plagioclase feldspar and biotite, hornblende, or augite. Sometimes porphyritic, that is having large, distinct crystals in a fine-grained groundmass. Included in the group of rocks collectively called felsite.

is an extrusive rock, mainly composed of plagioclase feldspar and pyroxenes. In Russia it is common on the large stratovolcanoes of Kamchatka. picture

A volcanic rock containing 53-63% silica with a moderate viscosity when in a molten state.

A dark-colored fine-grained rock of volcanic origin composed mainly of plagioclase feldspar (andesine) and one or more of pyroxene, hornblende or biotite. Andesite is named after the Andes mountains in South America.

a medium-gray-colored, fine-grained, usually extrusive igneous rock. It is intermediate in composition (half-way between felsic and mafic) and is the extrusive equivalent of diorite.

A light coloured volcanic rock made up of many tiny crystals

A fine grained, extrusive igneous rock with more silica content than basalt/gabbro, but less silica than rhyolite/granite. The coarse grained equivalent of andesite is called "diorite". Andesite is named after the igneous rock erupted by the many stratovolcanoes of the Andes mountain range in South America. Back

a fine-grained, extrusive volcanic rock named after the Andes mountain chain

A volcanic rock type intermediate in composition between rhyolite and basalt; the extrusive equivalent of diorite.

A dark gray volcanic rock containing 53-63 percent silica of moderate viscosity when in a molten state. Its composition and eruptive character is between basalt and dacite.

Fine grained brown or greyish volcanic rock.

an fine-grained, igneous rock, intermediate in composition between a rhyolite and a basalt.

volcanic rock with about 52% to 63% silica (silica is SiO2, an essential constituent of most minerals found in rocks).

Volcanic rock that contains between 56 and 63 weight percent silica. Andesites are typically gray or black in color and contain visible crystals of plagioclase, augite, and hypersthene (Figure 5).

Volcanic rock (or lava) characteristically medium dark in color and containing 54 to 62 percent silica and moderate amounts of iron and magnesium.

A dark coloured extrusive igneous rock composed of sodic plagioclase minerals (e.g. andesine), and mafic minerals that may include biotite, hornblende or pyroxene. Phenocrysts are often common and may comprise one or more of these minerals. Quartz is also often present in the matrix or 'groundmass'.

Volcanic igneous rock related to granite.

Andesite - A dark fine-grained basic igneous rock, usually with hornblende, pyroxene, biotite and calcic feldspar.

A dark-coloured, fine-grained, volcanic rock composed of feldspar and biotite, hornblende or pyroxene; the name is derived from the Andes Mountains; it is the volcanic equivalent of diorite.

A type of volcanic rock. Andesite is intermediate in composition between basalt and dacite, and contains about 60 percent silica. Andesite is common in volcanoes above subduction zones.

Fine-grained volcanic rock composed of andesine (plagioclase) with one or more mafic constituents.

A volcanic rock common in island arcs and mountain ranges.

Very fine crystalline extrusive rock of volcanic origin composed largely of plagioclase crystals with smaller amounts of ferromagnesian minerals.

A common intermediate lava.

Volcanic rock containing large amounts of silica, and some iron and magnesium.

A dark colored, fine-grained volcanic rock that, when porphyritic (contains visible crystals that grew out of the molten lava), contains phenocrysts (those crystals) composed mostly of the feldspar mineral Sodic Plagioclase.

fine-grained, dark-colored volcanic rock

A dark-colored, fine grained extrusive rock.

Igneous volcanic rock, less mafic than basalt, but more mafic than dacite; rough volcanic equivalent of diorite.

A volcanic rock of intermediate composition. It is fine-grained and contains 55 to 60 percent silica.

A variety of volcanic rock

volcanic rock, mesocratic, with a microlitic or porphyritic texture, composed of plagioclase (oligoclase/andesine), amphibole (green hornblende) pyroxene (augite) in a cryptofelsitic groundmass. In the paleovolcanic rocks, this groundmass contains secondary minerals : chlorite, epidote and opaque minerals.

Andesite is a type of volcanic rock. This gray to black rock is composed of about 54 to 62 percent silica (SiO2), plus some iron and magnesium.

An extrusive igneous rock of intermediate composition, often gray in color. The main minerals present in andesite are plagioclase and hornblende. The word “andesite” comes from the Andes Mountains in South America, where this rock type is common. Around the world, andesitic magma erupts out of volcanoes along convergent boundaries, and its intrusive equivalent is diorite.

A fine-grained, intermediate, extrusive igneous rock, usually found in volcanic arcs. Typically contains 53-62% SiO2 by weight.

A volcanic rock intermediate between basalt and rhyolite [LCOTE

A fine-grained, mafic volcanic rock consisting of both mafic minerals and plagioclase, and also usually containing quartz

A type of magma with intermediate viscosity and silica content. Forms large, steep sided volcanic cones composed of lava and pyroclastic material (for example, Mount Ruapehu). Andesite is also the name given to the volcanic rock formed from andesitic magma.

volcanic rock consisting mainly of oligoclase feldspar (medium term of the isomorphous series of plagioclase feldspars) and frequently including pyroxenes and magnetite (normally without or with very little quartz)

A fine-grained dark coloured volcanic rock;

A volcanic rock composed essentially of the mineral andesine and one or more mafic mineral constituents, such as pyroxene, hornblende, or biotite, or all three in various proportions.

Andesite (IPA: ) is an igneous, volcanic rock, of intermediate composition, with aphanitic to porphyritic texture. The mineral assembly typically is dominated by plagioclase plus pyroxene and/or hornblende. Biotite and quartz and iron-titanium oxides are common accessory minerals.