MATERIALS OF THE EARTH’S CRUST


The outermost part of lithosphere is called crust.

The material of the crust is made up of rocks.

The rocks are of different types.

They are hard like granite, soft like clay and loose like gravel.

Rocks are composed of minerals.

They are aggregates or physical mixture of one or more minerals.

Minerals, on the other hand, are made up of two or more elements in a definite ratio.

Minerals have a definite chemical composition.

The crust is made up of more than 2000 minerals, but out of these, 6 are the most abundant and contribute the maximum to this uppermost part of the earth.

These are feldspar, quartz, pyroxenes, amphiboles, mica and olivine.

Granite is a rock and its constituent minerals bound together are quartz, feldspar and mica which make it a hard rock.

Change in the ratio of these minerals gives rise to granite of different colours and hardness.

The minerals containing metals are called metallic minerals.

Haematite, a major iron ore is a metallic mineral.

Ores are metallic minerals.

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