Basalt is an extrusive igneous rock used in constructing buildings and statues. Extrusive rocks are also referred as volcanic rocks because volcanoes are important in their formation. When magma cools and hardens below the Earth's surface, an intrusive igneous rock forms.
Examples of intrusive igneous rocks are diorite, gabbro, granite, pegmatite, and peridotite. Extrusive igneous rocks erupt onto the surface, where they cool quickly to form small crystals. ... These rocks include andesite, basalt, obsidian, pumice, rhyolite, scoria, and tuff.
(e). Characteristics of Igneous Rocks. As described in some of the previous topics, igneous rocks are produced by the crystallization and solidification of molten magma. Magma forms when rock is heated to high temperatures (between 625 and 1200° Celsius) beneath the Earth's surface.
Igneous rocks are rocks which solidify from molten material (magma). Cooling of the magma can occur beneath the surface (plutonic) or on the surface (volcanic). Igneous rocks can be identified by the determination of the composition and texture of the rock.May 17, 2017
Igneous rock, also known as volcanic rock, is formed by the cooling of magma or lava. This type of rock is classified by cooling time and the type of magma it is formed from. The properties of these rocks vary greatly, including their chemical composition, grain structure, texture and color.Apr 24, 2017
IGNEOUS ROCKSWe can see from direct observation of volcanoes that some rocks crystallized from melt. ... Texture.Volcanic (extrusive)rocks fine grained because cools quickly. ... Plutonic/ intrusive rocks. ... Chemical and Mineralogical Composition. ... Mafic: Olivine, Pyroxene, Amphibole, Biotite.More items...
If the magma cools quickly, small crystals form in the rock. This can happen if the magma erupts from a volcano. Obsidian and basalt are examples of this type of rock. They are called extrusive igneous rocks because they form from eruptions of magma.