Black Basalt : basalt is an aphanitic (fine-grained) rock with generally 45-55% silica (SiO2) and fewer than 10% feldspathoid by volume, and where a minimum of 65% of the rock is feldspar in the form of plagioclase. It is the foremost common igneous rock type on Earth, being a key component of oceanic crust also because of the principal igneous rock in many mid-oceanic islands, including Iceland, the Faroe Islands, Réunion and the islands of Hawaii. Basalt commonly features a really fine-grained or glassy matrix interspersed with visible mineral grains. The average density is 3.0 gm/cm3.
Basalt is a hard, black extrusive igneous rock. Extrusive means it comes mainly from volcanic eruptions. It has a coffee silica incontent which enables this lava to flow quickly and allows volcanic gases to flee without explosive events. It is a fine grained rock and is that the commonest rock type within the crust .
Basalt underlies more of surface than the other rock type. Most areas within Earth’s ocean basins are underlain by basalt. Although basalt is far less common on continents, lava flows and flood basalts underlie several percent of Earth’s land surface. Basalt may be a vital 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 referred to as “lunar maria.” Large areas of the Moon are resurfaced by extensive basalt flows which can are triggered by major impact events. The ages of lunar maria are often estimated by observing the density of impact craters on their surface. Younger basalt flows will have fewer craters.
Olympus Mons is a shield volcano on Mars. It, like most other volcanic features on Mars, was formed from basaltic lava flows. It is the highest mountain on Mars and is the largest known volcano in our solar system.
Pavers and dimension stone. Basalt was used as stadium seating and street pavers throughout the Roman Empire. Today, basalt is usually used as crushed aggregate in construction projects. Crushed basalt is employed for road base, concrete aggregate, asphalt pavement aggregate, railroad ballast, filter stone in drain fields. But, basalt is also cut into dimension stone. In thin slabs it is used for building veneers, flooring, etc. and in its large columnar chunks it’s wont to create large durable stone objects, monuments, and even art. Thicker cut applications include basalt pavers.
