Igneous Rocks

Topic Content:

Igneous Rocks are formed when molten magma or lava cools and solidifies.

Igneous rocks contain crystals and are crystalline in structure, they do not contain any fossils. They are usually hard and difficult to penetrate once they are formed and do not have layers, they are non-stratified. Igneous rocks are either basic or acidic. Igneous Rocks also vary in size and colour. They are also known as primary or crystalline rocks.

Some rocks like basalt cool quickly and contain small crystals. Others like granite cool slowly and contain large crystals. Igneous rocks originate from the core or barysphere of the Earth where they are under great pressure and temperatures. When a crack develops in the crust of the Earth, the magma is forced through the crack. The molten rocks forced into the crust and towards the surface are called magma.

When the magma gets to the surface,