TYPES OF ROCK

Rocks are formed in different ways. We use them in a variety of ways.

What is in a rock? Rocks don't all look the same. They contain minerals which give them different colours and textures. Minerals in rocks sometimes from crystals that cna be polished and made into jewellery. Some rocks contain metals such as iron, tin or gold. Rocks are divided into three main types: igneous, metamorphic and sedimentary.

Igneous rock, like basalt and granite, are formed from the hot rock inside the Earth. Some of the melted rock or lava reaches the surface through volcanoes.

Metamorphic rocks, like slate and marble, have been changed by great heat or pressure inside the Earth.

Sedimetary rocks, like sandstone, are made from bits of other rocks, called sediments. They are washed away by rivers, settle into layers underwater and eventually become solid.