Mudstone facts for kids

These are some of the oldest rocks in the Dingle Peninsula. They formed during the Silurian period. These rocks are made of mudstones and siltstones, with some volcanic material. This picture was taken in County Kerry, Ireland.

A mudstone is a type of sedimentary rock. Sedimentary rocks are formed from bits of older rocks, minerals, or once-living things. They are often found in layers.

Mudstones are made from tiny pieces of rock and mineral. These pieces are called silt and clay. A mudstone must have at least one-third (1/3) silt and one-third (1/3) clay.

So, a mudstone is a kind of mudrock. It has a mix of different sized grains. Other mudrocks include siltstones and claystones. Some people even use the word "mudstone" as another name for "mudrock."

What is Claystone?

Claystone found in Slovakia.

A claystone is also a type of mudrock. It is mainly made of clay particles. These particles are very, very tiny. They are smaller than 1/256th of a millimeter.

For a rock to be called a claystone, at least half (50%) of it must be clay. Claystone does not break apart easily.

Related topics

• Mud

Images for kids

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  Mudstone on the east beach of Lyme Regis, England.

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  A Mudstone: You can see small parts in a fine-grained matrix. The picture is 32 mm wide.

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  A close-up photo of a carbonate mudstone, seen through a microscope.

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  This image shows where the Curiosity rover sampled rocks or soil on Mars, up to November 2016.

See also

In Spanish: Lutolita para niños