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Silicate minerals

The silicates are important building blocks in the Earth's crust. A limited number of the following minerals, found in the silicate rocks - olivines, pyroxenes, amphiboles, micas, feldspars and quartz, account for 90% of all igneous rocks.

An important feature of this particular mineral group is that they make use of a geochemical phenomenon called solid solution, where there is substitution of one cation in the structure of the crystal for another cation when it is forming, such that the chemical formula for the rock is not unique. Thus there is, for example, a rock diopside (a pyroxene) [(Ca,Mg)SiO3], which is made of a cross between members enstatite [MgSiO3], and wallonstonite [CaSiO3]. The fact that silicates rocks allow for molecule substitution makes them easy to take apart through weathering.

Structures are also important. The silicates come in several different structures of importance and these structures erode differently, leading to different strengths against weathering.


This drawing illustrates the fact that many different kinds of rocks are made of the same mineral building blocks.
Click on image for full size version (40K GIF)

Build your own silica tetrahedron model!

Go to a listing of Rocks by mineral group


Silicate minerals

The silicates are important building blocks in the Earth's crust. A limited number of the following minerals, found in the silicate rocks - olivines, pyroxenes, amphiboles, micas, feldspars and quartz, account for 90% of all igneous rocks.

An important feature of this particular mineral group is that they make use of a phenomenon where there is substitution of one molecule in the structure of the crystal for another molecule when it is forming. Thus there is, for example, a rock called diopside, which is made of a cross between enstatite, and wallonstonite. The fact that silicates rocks allow for molecule substitution makes them easy to take apart through weathering.

Structures are also important. The silicates come in several different structures of importance and these structures erode differently, leading to different strengths against weathering.


This drawing illustrates the fact that many different kinds of rocks are made of the same mineral building blocks.
Click on image for full size version (40K GIF)

Build your own silica tetrahedron model!

Go to a listing of Rocks by mineral group


The major types of minerals

Not applicable at this reading level.


This drawing illustrates the fact that many different kinds of rocks are made of the same mineral building blocks.
Click on image for full size version (40K GIF)

Build your own silica tetrahedron model!

Go to a listing of Rocks by mineral group



Last modified January 15, 1998 by the Windows Team

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