What is a basalt rock?

Basalt, extrusive igneous (volcanic) rock that is low in silica content, dark in colour, and comparatively rich in iron and magnesium. Basaltic lavas are frequently spongy or pumiceous; the steam cavities become filled with secondary minerals such as calcite, chlorite, and zeolites.

What does the word basalt mean in paragraph 7?

Primary sources on basalt are limited; however, Bernardino de Sahagún provides a brief description in his Florentine Codex – in Volume 11, Chapter 11, Paragraph 7, titled “Metlatetl: Stones from which metates are made.” (1) The word is a compound of “metl” meaning maguey, and “tetl” meaning stone.

Is basalt a real word?

Basalt (UK: /ˈbæs. ɔːlt, -əlt/; US: /bəˈsɔːlt, ˈbeɪˌsɔːlt/) is an aphanitic extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the surface of a rocky planet or moon. More than 90% of all volcanic rock on Earth is basalt.

What makes a rock basaltic?

Basalts are formed by the rapid cooling of basaltic lava, equivalent to gabbro-norite magma, from interior of the crust and exposed at or very close to the surface of Earth. These basalt flows are quite thick and extensive, in which gas cavities are almost absent.

How can you tell if a rock is 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 used for for kids?

One of the most abundant types of rock on Earth is basalt. It is a kind of igneous rock formed by the cooling of a certain type of molten lava. Because of its density and toughness, basalt is often used for making roads and in the construction of buildings. Basalt is found throughout the world.

What are the main components of black basalt?

Basalt consists mainly of iron and magnesium silicates, calcic plagioclase and pyroxene. Basalt has excellent technical characteristics not subject to alteration, a high degree of compactness with excellent resistance to mechanical stresses and shocks, low freezing and high slip resistance.

Does obsidian exist?

obsidian, igneous rock occurring as a natural glass formed by the rapid cooling of viscous lava from volcanoes. Obsidian is extremely rich in silica (about 65 to 80 percent), is low in water, and has a chemical composition similar to rhyolite. Obsidian has a glassy lustre and is slightly harder than window glass.

How hard is basalt rock?

On the Mohs scale of mineral hardness, basalt scores a six – meaning it’s harder than platinum or iron.

What are some examples of basaltic rocks?

Basalt is also an important rock type on other planetary bodies in the Solar System; for example, the lunar maria are plains of flood basaltic lava flows, and basalt is a common rock on the surface of Mars.

What gives basaltic rock its dark color?

The rock called basalt is formed by abundant dark minerals such as pyroxene and olivine , which make the basalt dark gray or black. Mineral content is the property of the rock that gives the rock its dark color.

What is basalt rock used for?

Today basalt rock is put to a variety of uses, most commonly as an aggregate. Crushed basalt is added to many construction jobs including asphalt paving, mixed with concrete, and as a rock filtering agent in many drain fields. It can also be cut into dimensional form and used as tiling for floors, producing veneers.

What volcano type is associated with basaltic rock?

Maar volcanoes are typical of small basalt tuffs, formed by explosive eruption of basalt through the crust, forming an apron of mixed basalt and wall rock breccia and a fan of basalt tuff further out from the volcano.