Introduction
Earth is a rocky or terrestrial planet. It is mostly covered completely by rocks.
Rocks
We can see rocks all around us.
Hills, mountains, boulders, etc., are made of rock.
Even the river and seabed are made of rocks.
The soil in our garden or sand in the beach is also rock.
The soil contains tiny particles of rock.
What you are standing on is also rock.
Different types of Rocks & their uses
There are many types of rock we see in nature. Rocks are hard, smooth, rough, permeable or impermeable.
Marble, Granite, Sandstone, Slate, Chalk, etc., are different types of rocks.
Hard rocks: Some rocks are harder than the others. For example, granite is a very hard rock and does not break easily.
Smooth rock: Chalk is a very soft rock and breaks easily.
Permeable rocks: Some rocks like sandstone or chalk allow water to soak through them. They are called permeable rocks.
Impermeable: Some rocks like marble and slate, do not allow water to soak through them. They are called impermeable rocks.
Slate
Slate is a hard, impermeable rock.
It splits into thin sheets, so it is good for making roofing tiles.
Writing slate that children use is made of thin layers of slate.
Marble
Marble has an attractive texture and colour. We can cut and polish it.
So we use it to make floor and wall tiles. Idols of goods are made of marble.
The Taj Mahal, one of the wonders of the world, is made of marble.
| Chalk | Granite | Sand stone |
|---|---|---|
| Chalk is a rock. It is formed from the remains of tiny sea animals. It is soft, so it is good for making sticks of chalk to write on blackboards. |
Granite is a coarse-grained rock. It is hard.It is used to make steps and roads. Granite is used to make kitchen slabs and flooring in our houses. |
It is a rock that contains compacted sand. It is small grains of rocks and minerals. Sandstone is a hard stone and does not wear away easily. It is used in building construction. The Red Fort is made of red sandstone. |
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