WHAT ARE ROCKS?

Rocks form the solid part of the Earth.
They are found everywhere in nature.
Some rocks are dark (basalt).
Others are light in colour (limestone).
Some rocks are formed by large grains (granite).
Others are formed by fine grains (clay).

Rocks in nature (from wikipedia)

Clay: fine grains (from wikipedia)

Limestone: light in colour (from wikipedia)

Granite: large grains (from wikipedia)

Basalt: dark colour (from wikipedia)