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 is also an abundant rock on the Moon. Much of the Moon's surface is underlain by basaltic lava flows and flood basalts. These areas of the Moon are known as "lunar maria." Large areas of the Moon have been resurfaced by extensive basalt flows which may have been triggered by major impact events. The ages of lunar maria can be estimated by observing the density of impact craters on their surface. Younger basalt flows will have fewer craters.
Basalt is a volcanic stone that has been used in architecture for centuries. basalt stone, one of the premium basalts in Stone Source's catalog of mate rials, has a particularly rich history. It is quarried near Rome and was used by the ancient Romans to build roads and monuments. Examples of its uses in architecture can still be seen still today. Basalts are rich in magnesium, feldspar, pyroxene and iron, with hints of olivine and amphibole; all of which are siliceous materials similar to those in a granite. Although Basalts boast the durability of a granite, they tend to have the consistent coloration, markings and subtlety of a limestone.
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