Rocks Meaning/definition ,types of rocks and their features

                    Meaning / definition

The elements  which are responsible for the formation of lithosphere generally called rocks . The word lithosphere in fact, means rocksphere as the literal meaning of ' lithos' is rock.

Nearly all rocks contain two or more minerals, that is to say rocks are composed of certain rock making minerals .

Types of rocks :- 

¹) IGNEOUS ROCKS

2)SEDIMENTARY ROCKS

3) METAMORPHIC ROCKS

1) igneous rocks:-

The word igneous has been derived from the latin word ignis, meaning fire , or those that were formed from cooling of a molten material, called igneous rocks 

Features:- 

a) layers are not exist in igneous rocks.

b) plants and animals are not found .

c) it is not usefull in agriculture.

d) igneous rocks are hard, massive and compact.

e) water cannot percolate in them.

2) sedimentary rocks:- 

The word sedimentary has been taken from the latin word sedimantum meaning settling down. Sedimentary rocks as the sediment implies are composed largely of fragments of older rocks, and minerals that have been more or less they are formed out of the sediments received from the priviously existing rocks.

Features:-

a) layers are found in it.

b) plants and animals are found in it.

c) it is useful for agriculture.

d) sedimentary rocks are soft in nature .

e) petrolium are found in sedimentary rocks.

3) metamorphic rocks 

Metamorphic rocks arise from the transformation of existing rocks types, in a process called metamorphism, which means " change in form".

Features:- 

a) metamorphic rocks are very hard in nature.

b) crystals are found in metamorphic rocks.

c) metamorphic rocks develop different set of minerals.

d) metamorphic rocks occupies 12% part of the earth land surface .

e) metamorphic rocks may have attractive bands of colour.