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Rocks - classification essay

All planets separated from a parent body as burning globes rotating in the space , including

our Earth . With time , this burning magma cooled down . As the process of cooling proceeded , the

surface of Earth was divided in two parts , land and water . The land portion consisted of the crust

of earth , which is known as rocks . There are three types of rocks- Igneous , Sedimentary and

Metamorphosis rocks

Igneous rocks are the first category of rocks . They were formed as a direct result of cooling of p

the magma , and involved a change in the state of matter from liquid to solid . The texture and the

composition are the two basic determining factors for igneous rocks Granite is a classic example

of igneous rocks . It consists of coarse granular structure , which can be seen with naked eyes

Technically these are Phaneritic igneous rocks

The second type Sedimentary rocks . These rocks are formed by the natural process of layers

Being deposited on the original rocks , mostly igneous . A thin veneer of loose sediments is

formed on the surface , and as time passes they by they get cemented together . Many times , this

type of rocks are also formed by joining of small pieces of large broken rock . A sea shore is one

of the examples of a sedimentary rock . Here , natural forces which help in continuous deposition

of sediments are very active

The third type is Metamorphic rock . This name is derived from `meta , meaning change and

`morph ' meaning form . It is formed when a rock faces great environmental changes related to

temperature and pressure . Mostly , buried dead bodies contribute to these changes . These changes

cause the minerals in the rock to loose their equilibrium and the rock is reformed as an effort to

restore that equilibrium . Slate is an example of metamorphic rock . This is formed when shale , a

sedimentary rock is subjected to variation in temperature and pressure

These are the three basic classification of rocks . All rocks are a result of ongoing natural

process , with little human intervention

References

What are the three basic types of rocks , Retrieved on 12 November 2007 from...