Igneous vs Sedimentary vs Metamorphic Rocks – Difference and Comparison

What are Igneous Rocks?

It is igneous rocks that are generated when molten material cools and solidifies, resulting in the formation of crystalline material. Because these rocks are formed from liquid (as opposed to sedimentary and metamorphic rocks, which are formed from pre-existing rocks). They are referred to as ‘primary’ rocks in the scientific community.

Because igneous rocks constitute 95 per cent of the upper layer of the earth’s crust, they are numerous. In addition, there are over 700 different types of these rocks to choose from. Granite is the most well-known of these igneous rocks, and it is used to make the vast majority of kitchen worktops.

What are Sedimentary Rocks?

Sedimentary rocks are formed by the weathering, transport, deposition, compaction, and cementation of pre-existing rocks and pieces of once-living animals. Sedimentary rocks are formed by the weathering, transport, deposition, compaction, and cementation of pre-existing rocks and pieces of once-living animals. These rocks are created at the bottom of water bodies such as seas and rivers over millions of years and are known as igneous rocks.

Depending on their chemical composition, sedimentary rocks can be divided into clastic, organic, and chemically precipitated. Clastic sedimentary rocks are formed due to the mechanical weathering of pre-existing rocks, and they are classified as such.

Organoclastic sedimentary rocks have formed as a result of the accumulation and deposition of the remains of dead plants and animals. When two minerals contained in rocks come into contact, a chemical reaction can occur. When the temperature is lowered, these minerals precipitate and form chemical sedimentary rocks.

What are Metamorphic Rocks?

As a result of changes in temperature and pressure, previously existing rocks undergo physical and chemical changes, which result in the formation of metamorphic rocks. To produce new rocks, the rocks are subjected to temperatures over 150 degrees Celsius and pressures over 1500 bar.

Metamorphic rocks can be divided into foliated rocks and non-foliated rocks. Foliated rocks are those that have been foliated, and Foliated rocks have a structure made up of thin layers, whereas non-foliated rocks are those that do not have this type of structure.

The majority of the earth’s crust is made up of metamorphic rocks, and it is a type of rock that can be found in abundance. Interestingly, because the Taj Mahal is entirely marbled, the monument can be considered a single massive metamorphic rock.

Difference Between Igneous, Sedimentary, and Metamorphic Rocks

  1. Rocks that are produced from molten material solidifying are called igneous. Sedimentary and metamorphic rocks, on the other hand, are formed from previously existing rocks.
  2. The crystalline structure of igneous rocks, the fragmentation and stratification of sedimentary rocks, and the foliation or non-foliation of metamorphic rocks are all characteristics of igneous rocks.
  3. Over 95% of the earth’s upper crust comprises igneous rocks, with the remaining 5% made up of all other types of geological formations and minerals.
  4. Metamorphic rock is a rock transformed by heat and pressure, unlike igneous rock, which is a rock formed in the earth’s crust or mantle.
  5. Granite, the most well-known igneous rock, is utilised in kitchen countertops. Throughout the world, rock salt, a sedimentary rock, is consumed. Building materials such as marble, a metamorphic rock, are frequently employed in constructing houses and other structures.

Comparison Between Igneous, Sedimentary, and Metamorphic Rocks

Parameters of ComparisonIgneous RocksSedimentary RocksMetamorphic Rocks
OriginThe molten material cools and solidifies to form igneous rocks (magma or lava).Pre-existing rocks, fossils, and microscopic fragments of animal life all contribute to the composition of sedimentary rocks.Metamorphic rocks are formed from other rocks.
FormationIgneous rocks are created during the cooling and solidification of molten material from volcanoes.This type of rock is created by water bodies depositing and cementing the sediments they contain.Metamorphic rocks result from the chemical and physical transformation of other pre-existing rocks under high pressure and temperature.
StructureCrystal-like structures predominate in igneous rocks.The interior layering of sedimentary rocks, referred to as bedding, is composed of fragments and is characteristic of sedimentary rocks.Hard, banded or stratified metamorphic rocks are common.
TextureHow quickly a piece of igneous rock cools affects the texture of that piece of rock. Coarse-grained to glassy textures are available.The texture is determined by the clast, age and depositional context of sedimentary r, and these tend to have a gritty texture.Because of the pressure, metamorphic rocks have a foliated texture. Some rocks appear to be banded and non-foliated.
TypesThere are two types of igneous rocks: intrusive (formed from magma deep under the earth) and extrusive (formed from the earth’s surface) (solidified from lava on the surface of the earth)Detrital, organic, and chemically precipitated sedimentary rocks are the three types of sedimentary rocks found in the earth’s crust.It is possible to divide metamorphic rocks into two basic categories: foliated and non-foliated.
ExamplesAs a rule, intrusive and extrusive igneous rocks are distinguished by Granite, diorite, and pegmatites.There are many different types of rock and minerals that make up the earth’s crust.Quartzite, hornfels and other hornfels-like rocks are examples of slate.


  1. https://www.sciencedirect.com/science/article/pii/0016714285900018
  2. https://link.springer.com/article/10.1007/s12517-013-0861-1