Rocks and their types

This article describes three types of rocks: Igneous, sedimentary, and metamorphic.

(1) igneous rocks, which solidify from molten material called magma.

(2) sedimentary rocks, which are made up of fragments from preexisting rocks or materials precipitated from solutions.

(3) metamorphic rocks, etc., are igneous or sedimentary rocks that have undergone considerable change in material composition, texture, and internal structure.

These three types are further classified into several groups and types based on many variables.

Chemical, mineralogical, and textural properties are by far the most significant.

Igneous rocks form when molten rock (magma or lava) cools and hardens. Sedimentary rocks form as particles settle out of water or air or when minerals precipitate out of water. They build up in layers. Due to heat, pressure, or reactive fluids like hot, mineral-laden water, existing rocks undergo metamorphism. 

The much more prevalent elements in the Earth’s crust are silicon and oxygen, which make up the majority of rocks.

A naturally existing and consistent combination of one or more minerals is called a rock in geology. These assemblages are the fundamental building blocks of the solid Earth, and they often take the shape of recognised and mappable volumes. As per the mechanisms that culminate in their development, rocks are categorised into three major kinds. 

Formation of Igneous Rocks: Igneous rocks are generated when molten lava, or magma, hardens. Intrusive and extrusive igneous rocks are the two types of igneous rocks.

Intrusive Igneous Rocks: The intrusive nature of Igneous rocks are well-known. Crystals in intrusive igneous rocks are formed when molten rock slowly cools beneath the Earth’s surface. Plutanic rocks, also known as intrusive rocks, are also a type of intrusive rock.

Igneous rocks which are intrusive in nature includes the following:

• diorite 
• gabbro 
• granite 
• pegmatite 
• peridotite

Extrusive Igneous Rocks: Extrusive igneous rocks are formed when molten rock bursts from the Earth’s crust and cools with crystals.

Extrusive igneous rocks include the following:

• andesite 
• basalt 
• dacite 
• obsidian 
• pumice

Igneous Rock Properties: Igneous rocks have a number of different qualities, but there are a number of common characteristics that can be used to identify them.

• All of them contain minerals.
• Silicate elements make up the majority of them.
• The production of igneous rocks cannot be viewed directly.
• They might be delicate or coarse in texture.
• When lava cools quickly, it often has a glassy appearance.

Sedimentary rocks:

These are the rocks that have been deposited throughout time.

Formation of Sedimentary rocks: These rocks form when layers of silt, sand, dead plant matter, and dead animal matter press together on or near the Earth’s surface. Clastic, chemical, and organic sedimentary rocks are the three types of sedimentary rocks.

The three types of Sedimentary Rocks are as following: 

Formation of Sedimentary Clastic Rocks: Clastic sedimentary rocks are made up of debris from mechanical weathering, or the process of rocks breaking down into smaller pieces. Inorganic detrital rocks are also known as inorganic detrital rocks.

Clastic sedimentary rocks ingredients:

• Breccia
• Conglomerate
• Sandstone
• Siltstone
• shale

Formation of Sedimentary Rocks with Chemical Compounds: Chemical sedimentary rocks are formed when dissolved minerals leave the water.

Chemical sedimentary rocks ingredients.

• evaporite 
• Castile 
• chert 
• flint 
• gypsum 
• iron 
• ore

Formation of Sedimentary Rocks with Organic Components: Organic sedimentary rocks are formed by animal and plant waste buildup. Organic detrital rocks are another name for these rocks.

Organic sedimentary rocks ingredients:

• coal
• coquina
• fossiliferous limestone

Qualities of Sedimentary Rock:

Sedimentary rock properties vary slightly from rock to rock.

• Clastic sedimentary rocks are made up of rock and mineral grains visible under a microscope or with the naked eye. 
• Igneous rocks have either a fragmental or crystalline texture.
• Sedimentary rocks are usually found on the surface of the Earth.
• The fossil record of prehistoric plants and animals can be found in these rocks.

Metamorphism Rocks:

Metamorphic rocks are subsurface rocks that have been altered by heat, pressure, and chemical processes. 

Metamorphic rocks are divided into two categories: foliated and nonfoliated.

Metamorphic Rocks with Foliation

Directed pressure and heat have made these rocks look banded or stratified.

The following are examples of foliated metamorphic rocks:

• Gneiss
• Phyllite
• Schist
• slate

Characteristics of Metamorphic Rocks

• Metamorphic rocks have a wide range of qualities since they all started as different rocks.
• The structure of metamorphic rocks is usually crystalline.
• They have a banded or crushed appearance.
• They do not become sufficiently heated to melt.
  

Conclusion 

These examples of many rocks can aid your exploration of the Earth’s geology. Igneous rocks form when molten rock cools and solidifies. Mineral composition and texture — the size and form of their mineral grains — are used to identify them.

Layers of sedimentary rocks can be found. Some occur when rock and mineral particles settle out of water or air. Others are formed when minerals precipitate from water. Minerals and texture are used to identify sedimentary rocks. Heat, pressure, and chemically reactive waters transform sedimentary, igneous, or pre-existing metamorphic rocks to generate metamorphic rocks. Minerals and texture are used to identify these rocks.