Answer: 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.
What is the description of basalt?
Basalt, extrusive igneous (volcanic) rock that is low in silica content, dark in colour, and comparatively rich in iron and magnesium.
How do you identify basalt?
Basalt appears black or grayish-black , sometimes with a greenish or reddish crust. Feel its texture. Basalt consists of a fine and even-grain. The dense rock has no crystals or minerals discernible to the naked eye.
What is basalt composed of?
Basalts are composed of minute grains of plagioclase feldspar (generally labradorite), pyroxene, olivine, biotite, hornblende, and less than 20% quartz . The mineral nepheline or leucite may associate or proxy the feldspar giving rise to verities with special names.
What is basalt short answer?
Basalt is a common extrusive volcanic rock , which is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet.
What are the examples of basalt?
Other examples include the Emeishan Traps of China , the Deccan Traps of India, the Keweenawan Lavas of the Lake Superior region, the Etendeka Basalts of Namibia, the Karroo Basalts of South Africa, and the Siberian Traps of Russia.
Is basalt acidic or basic?
Acidic rock is rock that is either siliceous, having a high content of silica (SiO 2 ), or rock with a low pH. The two definitions are not equivalent, e.g., in the case of basalt, which is never high in pH (basic) , but is low in SiO 2 .
What is the hardness of basalt?
The rock hardness of basalt is 6 as per the Mohs scale and can be observed through a combination of its compressive strength. Generally, 100-300 Mpa or Megapascal is the compressive strength.
Does basalt absorb water?
The importance of sealing Basalt tiles
All natural stones are porous to some extent, which means they may absorb liquids and moisture if exposed . Basalt is one of the denser natural stones, as compared to a material like sandstone but can still absorb unwanted contaminants over time.
What is the Colour of basalt?
Basalt is the volcanic equivalent of gabbro. Group – volcanic. Colour – dark grey to black . Texture – aphanitic (can be porphyritic).
Is gold found in basalt?
Gold is most commonly found along the edges of greenstone belts and associated with structural features. Intensely altered and fractured basalt is a common host rock. The gold is though to be mobilized by hydrothermal solutions during regional metamorphism.
What are some properties of basalt?
Basalt is rich in iron and magnesium and is mainly composed of olivine, pyroxene, and plagioclase. Most specimens are compact, fine-grained, and glassy. They can also be porphyritic, with phenocrysts of olivine, augite, or plagioclase. Holes left by gas bubbles can give basalt a coarsely porous texture.
Where can basalt be found?
It is found all over Earth , but especially under the oceans and in other areas where Earth’s crust is thin. It formed in the Isle Royale-Keweenaw region because of the Midcontinent Rift. Most of Earth’s surface is basalt lava, but basalt makes up only a small fraction of continents.
What is the purpose of basalt?
Basalt is used in construction (e.g. as building blocks or in the groundwork), making cobblestones (from columnar basalt) and in making statues. Heating and extruding basalt yields stone wool, which has potential to be an excellent thermal insulator.
What is basalt used for?
What is Basalt used for? Basalt is mainly used for structural building materials such as bricks, tiles, foundations and sculptures , as well as within stonewalls for thermal purposes and rail tracks. It can also be seen when looking at the moon as darker area which were formed from ancient lava flows.
Is a basalt rock?
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 quickly and easily move >20 km from a vent.
