Rock and Its Types

Rock: - It is the aggregate of one or more than one mineral. These rocks makeup our Earth’s crust, Rock are everywhere rocks are under the ground, forming mountains, they in the oceans, sea, and rivers etc. Mainly there are three types of rocks

1)      Igneous Rocks   2) Sedimentary Rocks    3) Metamorphic Rocks

1)      Igneous Rocks: -  Igneous Rocks are the rocks formed from the crystallization of magma or lava, when the magma or lava crystallize the Igneous Rocks starts to formed under the surface and on the surface. Olivine, Pyroxene, Amphibole, Mica, Quartz and Feldspar are the commonly found in Igneous rocks. The Igneous rocks are somehow different from each other the reason is that the rate of cooling of magma. Some common Igneous rocks on the basis of depth.

Plutonic Rock	Volcanic Rocks
Granite	Rhyolite
Granodiorite	Dacite
Tonalite	Quartz Andisite
Syenite	Trachyte
Monzonite	Latite
Diorite	Andisite
Gabbro	Basalt

Igneous Rocks are classified on the basis of Texture, Mineralogy, and chemical composition etc.

2)      Metamorphic Rocks: - Metamorphic Rocks formed under high temperature and pressure Metamorphic Rocks also formed from pre-existing rock. Alteration of mineralogy and texture of Igneous and Sedimentary rock due to high pressure and temperature makes Metamorphic rocks. Metamorphic rocks are classified on the basis of texture

a)      Foliated Metamorphic rock: - The rocks which have foliation generally for Foliated Metamorphic rocks the term Grade is use to distinguish the Metamorphic rocks.  High to low grade Metamorphic rocks, they are as follow

b)      Non- Foliated Metamorphic rock: - Foliation does not occur in these rocks these rocks are formed by contact metamorphism.

 The agents of metamorphism are as follow:

                                I.            Temperature     ii) Pressure         iii) Stress and Strain         iv) Fluids

3)      Sedimentary Rocks: - Sedimentary Rocks are formed from the weathering and Erosion of pre-existing rocks such as Igneous and Metamorphic.

As Igneous and Metamorphic rock are important for minerals occurrence same as Sedimentary rock are very important for Hydrocarbons, fossils and ground water etc. The sedimentary rocks are classified into a two types

A.      Clastic  Sedimentary rocks

Ø  Sandstone

Ø  Mudstone

Ø  Conglomerates

B.       Chemical Sedimentary rocks/ Non

Clastic SR

Ø  Carbonate

Ø  Siliceous Oozes/ Cherts

Ø  Evaporites