How Many Types of Rock Are There?

Edited By Team Careers360 | Updated on Mar 20, 2023 05:13 PM IST

There are mainly three types of rocks, namely:

Rocks are mineral aggregates with mineral traces and have a combination of various properties.
They have a unique combination of chemical composition, mineralogy, grain size, texture, or other distinguishing characteristics that can describe rock types.

Igneous rock

They are formed by the cooling and solidification of lava or magma.
They may or may not be crystalline in structure.
Rocks with crystallisation on the rock surface are known as extrusive or volcanic rocks.
Rocks with crystallisation under the rock surface are known as intrusive or plutonic rocks.
Magma can be formed from the partial melting of existing rocks on the earth's crust or mantle.
Melting includes one or more of the following three processes:

They are formed by the deposition of material within water bodies or on the surface of the earth.
Sedimentation is the process by which various organic materials and minerals settle down in a place.
The particles that get accumulated to form rock are known as sediments.
Sediments can be formed by weathering and erosion or transported from one place to another through the air, water, ice, wind, and glaciers. All of them are known as agents of denudation.
Sedimentation in water takes the form of mineral precipitate from a water solution or the shell of aquatic creatures.

There are three types of sedimentary rocks.

Clastic sedimentary rocks are formed from the mechanical weathering of debris.
Chemical sedimentary rocks are formed from dissolved minerals that precipitate over time.
Organic sedimentary rocks are formed from plant and animal debris.

They make up a large part of the earth's crust.
They are classified based on their texture, chemical composition, and mineral composition.
They are formed deep beneath the earth's surface.
They arise from the metamorphosis of existing rocks.

There are two types of metamorphic rocks.

Foliated: They are produced by exposure to heat and pressure, which gives them a layered appearance.
Non-foliated: They don't have layers.

Archaean system rocks are formed from hot molten earth.
The rock of the Dharwar system was formed from the erosion and sedimentation of the Archaean system.
Cuddapah system rocks: formed by Dharwar system erosion and sedimentation.
The rocks of the Vindhyan system are formed from the slits of valleys and oceans.
rocks of the Gondwana system: formed from depressions in basins
Rocks of the Deccan Trap: formed from volcanic eruptions
Rocks of the Tertiary System: found in the Himalayan region
Rocks of the Quaternary system: found in the Indus and Ganga plains