The shape, structure and texture of a basalt is diagnostic of how and where it erupted—for example, whether into the sea, in an explosive cinder eruption or as creeping pāhoehoe lava flows, the classic …

Basalt is a dark-colored, fine-grained, igneous rock composed mainly of plagioclase and pyroxene minerals. It most commonly forms as an extrusive rock, such as a lava flow, but can also form in …

Dec 20, 2025 · Basalt, extrusive igneous (volcanic) rock that is low in silica content, dark in color, and comparatively rich in iron and magnesium. Basalts may be broadly classified on a chemical and …

Apr 10, 2018 · Basalt is the most abundant volcanic rock on Earth, covering more than 90% of the ocean floor and large continental regions shaped by ancient lava flows. It forms when mafic magma, …

Basalt is defined as a fine-grained, dark-colored igneous rock composed mainly of plagioclase and pyroxene minerals, with or without olivine. It is formed from the rapid cooling of basaltic lava exposed …

Dec 14, 2012 · Basalt is a very common dark-colored volcanic rock composed of calcic plagioclase (usually labradorite), clinopyroxene (augite) and iron ore (titaniferous magnetite). Basalt may also …

Basalt is a hard, black volcanic rock with less than about 52 weight percent silica (SiO2). Because of basalt's low silica content, it has a low viscosity (resistance to flow). Therefore, basaltic lava can flow …

Basalt (UK: / ˈbæsɒlt, - ɔːlt, - əlt /; [1][2] US: / bəˈsɔːlt, ˈbeɪsɔːlt /) [3] is an aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low- viscosity lava rich in magnesium and …

Basalt is a common, gray to black volcanic rock. It is usually fine-grained due to rapid cooling of lava on the Earth's surface. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or …

Basalt and related rock types like andesite and dacite are rocks that form when volcanoes erupt magma (lava) onto the surface of the earth and the magma cools. Basalt flows on Hawaii.