Sand & Gravel Quarry
How rocks are made
The outer part of the Earth on which we live is called its crust. The crust is 40 kilometres thick – ten times the depth of the world’s deepest mine in South Africa - and made up of three main types of rock.
Rocks come in a huge variety of shapes, textures and colours, but they’re all made in one of just three ways.
Geologists classify rocks into three types according to the different ways in which they’re formed:
- Igneous (pronounced ig-knee-us)
- Metamorphic (met-a-more-fic)
- Sedimentary (sed-ee-ment-ary)