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What do you mean by rocks? Name the three major classes of rocks

Question: 

What do you mean by rocks? Name the three major classes of rocks

Answer:

The main source of rocks is magma, when magma cools it becomes rock. The upper layer of our earth, which is the crust, is made up of rocks.

Following are the salient features of rocks:

  • The composition of the rock is minerals, Rocks may be made up of one or more minerals.
  • Rocks can be hard or soft. For example, granite is hard and soapstone is soft.
  • The color of the rocks varies. For example, gabbro rock is black and quartzite is usually milky white.

On the basis of formation, rocks can be classified into three major classes:

  • igneous rock
  • sedimentary rock
  • metamorphic rock


Igneous rocks are formed by the cooling of magma.

Sedimentary rocks are formed by the deposition of smaller particles of rocks by exogenous processes.

Metamorphic rocks are formed by the recrystallization of existing rocks.

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