Different types of rocks, Uses of stone

The portion of earth crust having no definite shape and structure, While Stone usually means piece or block of basic material. Types of rocks

Classification of rocks

There are 3 types of rocks classification

• Geological Classification
• Physical Classification
• Chemical Classification

Geological classification of rocks

According to this classification of rocks, The rocks are of the following three type.

Igneous rocks:

The freezing of molten material forms rocks directly, either inside or on the surface. Igneous rocks known as a parent rock. And its other name are primary rock, polymineralic rock, eruptive, and mother rock.

• Plutonic Rocks : These rocks are formed cooling of magma at considerable depth form earth surface. Other name is intrusive rock.
• Hypabyssal rocks: Formed relatively shallower depth & cooling quick.
• Volcanic rocks: Formed by pouring of magma at earth surface & cooling very quick. Other name are extrusive rock, effusive rock.

Sedimentary rock:

The rocks formed by consolidation of pre-exiting rock under the effects of weathering are carried away from their origin by the agents of transport, Agents are frost, rain, wind, flowing, water etc. For example of Sedimentary rocks are lime stone (Caco₃), dolomite, sand stone, shale etc.

• Residual Deposits: when some portion of weathering particle remain at site of origin.
• Sedimentary Deposits: The insoluble product of weathering are carried away in suspension
• Chemical Deposits: Carried away in solution may be deposited by some physio-chemical process as evaporation precipitation

Metamorphic Rocks:

Metamorphic rock formed from pre-exiting rock due to variation in temperature (great heat) or pressure or both. Eg. Marble, Slate, Gneiss etc.

• Thermal metamorphism: The heat is the predominant factor in this type of metamorphism.
• Cataclastic Metamorphism: At the surface of earth, the temperature are low and metamorphism is brought about only by the directed pressure.
• Dynamo: thermal metamorphism: Rise in temperature with in depth.
• Plutonic metamorphism: Metamorphic changes at great depths are therefore brought about by uniform pressure and heat.

Physical Classification of rocks

According to physical classification, There are three types of rocks

• Stratified rocks: which rocks easily split into layers are called stratified rock.
• Unstratified rocks: which rock are not split into layer, The structure may be crystalline granular or compact granular.
• Foliated rocks: Rocks have a tendency to be split into definite direction only.

Chemical Classification of rocks

This Classification also known as scientific or engineering classification. According to chemical classification, There are three types of rocks.

• Siliceous rocks: It is necessary that these rocks should contain maximum amount of free silica for making them hard and durable .
• Argillaceous rocks: The argil or clay Predominates, rock may be dense and compact or they may be soft.
• Calcareous rock: Calcium carbonate predominates, the durability of these rocks will depend upon the constituents present in the surrounding atmosphere.

Uses of stones:

• Sand Stone- Generally we are use this stone in building work
• Marble stone are used for architectural beauty
• Light sand stone are used for bridge
• Basalt or trap granite are used for railway ballast aggregate for concreting
• Gneiss & granite used for Heavy work like bridge piers
• Granite used for Industrial town
• Sand stone used for fire & proof building
• Lime stone used for manufacture of lime