Igneous rock is better known as ‘Fire Rock’ to the people. The word ‘igneous’ is derived from the Latin word ‘ignis’, means ‘fire’. It is also called magmatic rock.
When magma or lava becomes solid then it is formed in the shape of igneous rock. The magma is gotten from some partial melts which already exist in the rocks, these are from the mantle or crust. The melting of magma or lava is caused by at least three processes:
- An increase in the temperature
- A decrease in the temperature
- A change in the composition
Igneous Rock
Igneous rock is formed usually with granular crystallization. Sometimes it works like natural glasses. Igneous rock occurs usually in a wide range of geological settings: shields, platforms, orogens, basins.
Identification of Igneous Rocks and Minerals
To identify if the rock is Igneous Rock or not you must look for four criteria:
- Chemical Composition
- Mode of occurrence
- Mineralogy
- Texture
Igneous Rock is collected in various sizes. Particle and size are different according to the classification size of the rocks and those depend on the cooling history and also on the properties of the rock. In the formation of Igneous Rock, there is quartz, olivine, feldspars, micas, pyroxene, and amphiboles. Sometimes other minerals are presented too. Some minerals are still unknown. They are called ‘accessory minerals’.
Types of Igneous Rock
If you talk about availability and kinds there are almost 700 kinds of Igneous Rock. They are created earth’s crust. Because of the volcanic eruptions, Igneous Rock does not form frequently. Followings are the major types of Igneous rocks:
- Andesites
- Basalt
- Pumice
- Gabbro
- Granite
- Diorite
- Rhyolite
- Obsidian
- Welded Tuff
Brief descriptions of these types are given below:
Andesites
Andesites are gray in color. These are simply fine-grained igneous rocks. Minerals that are got into it are plagioclase minerals, biotite, pyroxene, hornblende. These fine-grained rocks are important for ornament business. They are chosen for their fine blending and their not so edgy stone.
Basalt
Basalts are actually fine-grained rocks. They come in dark gray color. They have good density. Minerals in that is plagioclase and pyroxene. Basalts are called solidified lava. This is used in the building and construction process. These are the volcanic or extrusive rocks. Intrusive cannot be formed. Basaltic rocks are got in the rocks of the moon and mars. It is used in flooring, cobblestone, countertops, and railroad track ballast.
Pumice
This is an actually vesicular igneous rock. It results from solidification of magma. It is also used as hand-soaps, emery boards. You can call it a household product. You can also it in cosmetics and construction works. This is a very heavy weight and high porosity rock. The holes in it are the holes recognizing part.
Gabbro
These Igneous Rock come dark in color. It consists of feldspar, pyroxene, and olivine. Sometimes the color can turn into gray. They have small spots in them. As this falls under the plutonic type, it differs in texture. When polished, it can be used for multiple purposes like making cork surface, floor tiles, facing stone and cemetery markers. Gabboros are usually used in road-related works like forming concrete aggregate, ballast for railroads and road metal.
Granite
Granite comes in a light color. These are the coarse-grained intrusive Igneous Rock. It consists of three minerals mainly mica, feldspar, quartz. Colors can vary. They are in gray, tan and pinkish. It is used in architectural and construction sites. This is also used in making ornaments. It's available in large quantities and has good strength. These are also used in decorative monuments, bridges, and commercial buildings.
Diorite
These are also the coarse-grained intrusive Igneous Rock. It has minerals named pyroxene, hornblende, feldspar, and quartz. These are light in color. Sometimes they have darkened spots. This is the hard Igneous Rock. This is used for inscriptions, for making statues and carvings on rocks. Nowadays the function of diorite is restricted. It is used in flooring and landscaping. It has weather-resistant agents in it.
Rhyolite
These are the fine-grained rocks. These are light in color. It consists of quartz and feldspar minerals. It has a smooth surface. It has a smooth surface. It has high acidity in it. It is an extrusive volcar rock. These are in porphyritic texture. It can also be used for ornamental purposes. It is used as an abrasive and sourcing stone.
Obsidian
Obsidian is dark in color. It has a good density in them. These are formed rapidly after the cooling crystallization process. They are crystal-like and slim-looking. It is used in making scalpel blades, ornament and decorative specimens. It is also used as a mineral source. These minerals sources are important for nature.
Welded Tuff
This is actually volcanic igneous rock. It is gotten in a volcanic eruption. It fells on the earth surface. It turns into rock through lithification. These are made of volcanic ash and they have a good particle. It is used especially for welding purposes.
This is all about Igneous Rock today. There are more that we do not know much about. These are sconia, peridotite, pegmatite, and estate. From all of these, basalt is the common one. But granite is mostly found among all of them. This is an overview of all types of Igneous Rock. There good uses and availability are very much important for us as they are used for various purposes. The ornaments sector mostly depends on it as it has the good purpose of using it. Their color, texture and their availability are important for nature too.