basalt what is it
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 small intrusive bodies, such as an igneous dike or a thin sill. It has a composition similar to gabbro.The difference between basalt and gabbro is that basalt is a fine-grained rock while gabbro is a coarse-grained rock. Basalt underlies more of Earth's surface than any other rock type. Most areas within Earth's ocean basins are underlain by basalt.t has a composition similar to gabbro. The difference between basalt and gabbro is that basalt is a fine-grained rock while gabbro is a coarse-grained rock. Basalt underlies more of Earth's surface than any other rock type. Most areas within Earth's ocean basins are underlain by basalt.