Home > Rocks > Sedimentary Rocks > Chemical Sedimentary Rocks

Unlike detrital sedimentary rocks, which contain fragments of pre-existing rocks or minerals, chemical sedimentary rocks typically consist of crystals derived from different compounds.

Characteristics
Chemical sedimentary rocks have small crystals. Some chemical rocks are organic (contain the element carbon or have been made from living organisms) and will cause hydrochloric acid to fizz when it is dropped onto them.

How they are formed
When water washes over and through rocks, some of the minerals from the rocks are dissolved and carried in the water. When the water evaporates or the minerals precipitate out of it the chemical sediment (the previously dissolved minerals) are deposited. These sediments go through the same lithification process as detrital sedimentary rocks.

Where they are found
Chemical sedimentary rocks are found all over the world. Layers of these rocks can be seen in places where rock has been cut to put a road through. Some famous chemical sedimentary rocks are limestone in Pennsylvania and caves, and coal.

Click here to view Detrital Sedimentary Rocks

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