Igneous rock is made up of two words; on the one hand, rock is a very solid stone that is made up of one or more minerals, and on the other hand, igneous is linked to fire. Therefore, igneous rock is defined as a rock that is created by slow or rapid cooling and solidification of magma, which is found within the earth’s surface.
There are several types of igneous rocks and they are as follows:
- Intrusive or plutonic: it is the one that arises through the slow cooling process and forms rocks with large crystals.
- Extrusive or volcanic: it is the one that arises through the rapid cooling process and forms rocks with transparent crystals.
examples of igneous rocks
Granite is a plutonic igneous rock formed from quartz, alkali feldspar, plagioclase and mica, and is commonly used by architects for flooring and kitchen design.
Basalt is an igneous volcanic rock with a very dark hue and composed of calcium-rich plagioclase, pyroxenes, amphiboles, and olivine. It is characterized by being one of the most in the entire crust of planet Earth.
Obsidian is an igneous volcanic rock with a vitreous texture that was widely used in prehistory and is made up of aluminum silicates and a large percentage of silicic oxides. It is characterized by its conchoidal fracture and can be both transparent and dark.
Peridotite is an ultramafic intrusive rock that is made up of olivine, pyroxene, and amphibole, and is one of those found in the Earth’s mantle . It is used as an ore for magnesium and iron and is very dense and dark in color.
Granodiorite is an intrusive igneous rock with a phaneritic texture similar to granite, a light gray color and also pinkish. The composition of this rock is quartz, oligoclase, potassium feldspar, biotite and amphibole.
Dacite is an igneous volcanic rock with a high content of iron and silica , it also has an aphanitic and porphyritic texture with very large crystals. It is generally found in the continental crust, which in turn is the well-known continental shelf.
More examples of igneous rocks
Pumice or pumice stone is a low-density, porous, vitreous volcanic igneous rock that floats on water and has a whitish or grayish hue . This rock is very easy to find in very violent and explosive eruptions due to the pressure of the gases.
Porphyry is a Filonian rock very similar to granite and has been widely used in construction since time immemorial, both for its decorative appearance and for its hardness. It is formed by crystals of feldspar and quartz included in a dark red mass.
Komatite is an extrusive igneous rock that is unique to the geologic period that ended 2.5 billion years ago.
This is formed through very hot magma and is characterized by being fluid and rich in magnesium, it also has a knife-shaped olivine texture surrounded by a matrix of dendritic chromite, altered glass and spherulitic clinopyroxene.