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Quartzite
Quartzite is a metamorphic rock formed from hard sandstone. It is found in

yellow, brown, pink and red colours.
Gneiss
Gneiss is a metamorphic rock formed from granite. It has irregular bands of

different colours.

MINERALS

A mineral is an underground natural resource having
chemical composition. Except animals or plants,

everything is said to be a mineral. Quartz, feldspar
and mica are the major rock forming minerals. Rocks
are composed of different minerals in different

proportions. These are all found in granite.
In addition to the major rock forming minerals,
Diamonds
smaller amounts of other minerals are also found in
particular kind of rocks. Minerals containing metals

like copper, silver, aluminium and iron are called ores .
Bauxite is the chief ore of aluminium. Haematite is an

ore of iron. Copper pyrite is an ore of copper.
Some rocks contain valuable non-metallic minerals
such as graphite and borax . Gems are precious

stones. Most gems come from rocks. Diamonds ,
mined in Africa and USA, come from a rock called

peridotite. Minerals are very useful to human beings. Borax

USES OF ROCKS AND MINERALS

w Quartz and mica are used in electronic industry.
w Minerals like nitrates, phosphates and sulphates
are used as fertilizers.

w Talc is used for making talcum powder.
w Limestone is used for making cement.

w Platinum, gold and silver are useful for making
jewellery.

w Graphite is used for making pencil leads. Graphite

w Metals like aluminium, silver and copper are used for making utensils and

coins.

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