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Chemical Weathering

Chemical weathering is the breaking down of rocks by chemical reactions. It takes place in almost all types of rocks. This happens a lot with smaller rocks because they have a greater surface area for their size.
Rusted Bolts

Rust. Rust, also known as oxidation, is a form of chemical weathering.

Chemical weathering can take many forms. Like many other types of weathering, this can be a very long process. 

What is Chemical Weathering?

Chemical weathering is a type of weathering that is fueled by chemical reactions. These reactions occur between rocks and their environment. Because rocks exist in so many different places, there are many types of weathering. Water is a huge source of this kind of weathering. This is because water reacts with a lot of the most common minerals found in rocks.
An example of an eroded rock.

Water can weather rocks into strange formations that look like the inside of beehives!

Water can combine with the minerals in rocks to form clay and other weaker substances. These new substances can be much easier to erode than the original rock! This process is called hydrolysis.


Oxidation is a type of chemical weathering caused by the oxygen in the air. This occurs when oxygen combines with another substance to form an oxide. A common example is when iron and oxygen combine to form iron oxide, also known as rust! Another is ore; ores are deposits of oxidized elements (like iron).
The Rainbow Mountain in Peru.

This beautiful landscape is in Peru and called Rainbow mountain. It is the result of oxidation and erosion!

Oxidation often also requires water. This is another reason why so much of chemical weathering occurs near water! Rust and other oxides are much weaker than the original rocks. This makes the rocks much easier to weather and erode.

Examples of Chemical Weathering

In big cities, there are a lot of sources of burning fuel that leak chemicals into the air. Once enough of these chemicals are in the air, they react with rainwater to form acid rain! This acid rain can weather the concrete and other rocks in the city.
Caves provide the perfect environment for water and oxygen to react with minerals. Caves give plenty of time for chemical reactions to weather the rocks inside.
Stalagmites and Stalactites

These stalagmites are the results of calcite in the rocks dissolving with water as it drips down from the cave’s ceiling.

Other Great Resources

What is Chemical Weathering? – American Geosciences Institute:  https://www.americangeosciences.org/education/k5geosource/content/rocks/what-is-chemical-weathering
Types and Examples of Chemical Weathering – Thoughtco: https://www.thoughtco.com/examples-of-chemical-weathering-607608
Weathering and Erosion – Crash Course Kids: 

Written By: Jesus Cervantes.