General Awareness Rocks

Rocks

`color { maroon}ul{"Rocks"}`
Earth’s crust is composed of rocks. Its an aggregate of one or more minerals. Rocks do not have definite composition of mineral constituents. However, feldspar and quartz are the most common minerals found in rocks.

Based on their mode of formation, there are three different types of rocks:

`=>` Igneous rocks – solidifies from magma and lava.
`=>` Sedimentary rocks – the result of deposition of fragments of rocks by exogenous processes.
`=>` Metamorphic rocks – formed out of existing rocks undergoing recrystallization.

`color{green} ✍️ ` The solid part of the Earth's crust are called rocks.

`color{green} ✍️ ` A rock can be defined as an aggregate of minerals and contains organic compounds.

`color{green} ✍️ ` They come in infinite sizes, shapes, colors, weights, textures and strengths.

`color{green} ✍️ ` Rocks are classified in three main types depending on the process of their formation.

1. Igneous
2. Sedimentary
3. Metamorphic

Igneous Rocks

`color { maroon}ul{"Igneous Rocks"}`
Extrusive igneous rocks cool and solidify quicker than intrusive igneous rocks. They are formed by the cooling of molten magma on the earth's surface. The magma, which is brought to the surface through fissures or volcanic eruptions, solidifies at a faster rate.

`color{green} ✍️` Formed due to the cooling, solidification and crystallisation of hot and molten magma.

`color{green} ✍️` Igneous means 'firery' (from heat or fire).

`color{green} ✍️` Such rocks do not contain fossils or organic matter.

`color{green} ✍️` They are called as the primary rocks as all the other rocks are formed directly or indirectly from the igneous rocks.

`color{green} ✍️` They are hard, granular and crystalline rocks, less affected by chemical weathering.

`color{green} ✍️` There are about 700 different types of igneous rock.

`color{green} ✍️` Moreover, it does not have any fossil or does not form any strata or layers of lava,
e.g. of Igneous rocks-Granite, Basalt, Gabbro, Pegmatite and Peridotite.

Uses of igneous rocks:

`color{green} ✍️` Granite is used for building and construction because of its strong properties.

`color{green} ✍️` It is also used for head stones and kitchen counter tops.

`color{green} ✍️` Pumice is lightweight and has lots of air spaces.

`color{green} ✍️` It is used by cosmetic and cleaning industries to make things like excess skin removing stones.

`color{green} ✍️` It is also used in some toothpaste products because of its abrasive nature.

Sedimentary Rocks

`color { maroon}ul{"Sedimentary Rocks"}`
Sedimentary rocks are types of rock that are formed by the deposition and subsequent cementation of that material at the Earth's surface and within bodies of water. Sedimentation is the collective name for processes that cause mineral or organic particles (detritus) to settle in place.

`color{green} ✍️` It is formed due to the aggregation and contraction of sediments derived from the older rocks, plants, animals and contains fossils of plants.

`color{green} ✍️` The sedimentary rocks can be classified on the basis of the nature of sediments mechanically, chemically and organically formed rocks.

Metamorphic Rocks

`color { maroon}ul{"Metamorphic Rocks"}`
A metamorphic rock is a result of a transformation of a pre-existing rock. The original rock is subjected to very high heat and pressure, which cause obvious physical and/or chemical changes. Examples of these rock types include marble, slate, gneiss, schist.

`color{green} ✍️` These are the changed form of igneous and sedimentary rocks.

`color{green} ✍️` These are the rocks, which change either in form or composition without disintegration.

`color{green} ✍️` Already formed metamorphic rocks are metamorphosed and this process is called metamorphosis.

`color{green} ✍️` The agents of metamorphism are: heat, compression and solution.

 
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