The Clays

The clays are very important because they are the end products of weathering, see this example.

All of the clay minerals are sheet silicates. Each clay type owes its distinctive character to the cations, such as sodium, potassium, magnesium, or calcium, that occupy positions in and between the sheets. Smectite, for example, has a structure and cation composition that gives it the ability to soak up large quantities of water. Kaolinite absorbs less water but is just right for making pottery and creamics.

Another example is montmorillonite, (Al,Mg)8(Si4O10)3(OH)10.12H2O. Clay minerals are essentially hydrous aluminum silicates. They are major minerals in the weathering process. Montmorillonite and nontronite are considered to compose roughly 20% and 50%, respectively, of volcanic weathering products. The open crystal structure allows them to absorb and hold large amounts of chemically bound water.

Some of these clays have recently been found on the surfaces of the Jovian moons Ganymede and Europa, implying water hydration processes on these worlds.


This is a view of the Earth.
Click on image for full size version (40K GIF)
Image from: NOAA

Go to a listing of Rocks by mineral group


The Clays

Clay, which is sometimes used in schools or to make pottery, is found in the earth and sometimes has some fancy names. Common clays include

The clays are very important because they are the end products of weathering, see this example.

Montmorillonite and Nontronite, for example, are considered to compose roughly 20% and 50%, respectively, of volcanic weathering products. The open crystal structure allows them to absorb and hold large amounts of chemically bound water. Smectite has a structure that gives it the ability to soak up large quantities of water. Kaolinite absorbs less water but is just right for making pottery and creamics.

Some of these clays have recently been found on the surfaces of the Jovian moons Ganymede and Europa, implying water hydration processes on these worlds.


This is a view of the Earth.
Click on image for full size version (40K GIF)
Image from: NOAA

Go to a listing of Rocks by mineral group


The major types of minerals

Not applicable at this reading level.


This is a view of the Earth.
Click on image for full size version (40K GIF)
Image from: NOAA

Go to a listing of Rocks by mineral group



Last modified November 15, 1997 by the Windows Team

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