Different types of rock

There are three main types of rock: sedimentary, metamorphic and igneous.

Rocks are different because of differences in how they are formed, but all the rock types are linked through the rock cycle.

The rock cycle worksheet

Sedimentary rocks

In this part of the workshop we are going to explore sedimentary rocks. What they are, how they are made and where we can find them.

Sedimentary rocks are made from sediment which can include pebbles, rock fragments, and sand. Sedimentary rocks can also contain fossils, ranging from small pieces of shell to dinosaur remains!

Follow the video and add the pictures and facts below to your rock cycle worksheet.

Describe a Sedimentary Rock

There are lots of different types of sedimentary rock. What they look like depends on what kind of sediment they are made from.

Explore some of the sedimentary rocks in the GeoBus collection below. Move your mouse over the top of the first image to find out more about that rock.

Sandstone

This orange sandstone is made of lots of tiny sugar-like grains of sand. It has a rough texture, similar to a sugar cube. Sandstone is a common building material as it is relatively soft and can be carved easily.

Conglomerate rock

‘Conglomerate’ is a way to describe rocks that are made up of other smaller rocks such as pebbles and grains. If you look closely at this conglomerate, you can see that it is made of grey fragments of rock that are held together by very small red grains.

Limestone

This limestone is a creamy-beige colour and has lots of small bits of fossilised shell inside. Limestone typically forms underwater from sediment building up over long periods of time. Because of this, it is common to find the fossils of sea creatures in limestone, such as ammonites and trilobites.

Famous Rocks: The Grand Canyon, Arizona

The top layers of the rocks that you see in the Grand Canyon are sedimentary rocks. Use the 3D model to explore these extraordinary rocks up close!

Grand Canyon by Ignazio Pillitteri on Sketchfab

Optional Activity: Bake a sedimentary rock!

Make an edible sedimentary rock

Proceed to Part 3: Igneous Rocks