Clay

Clay is a naturally occurring material composed primarily of fine-grained minerals, which show plasticity through a variable range of water content, and which can be hardened when dried or fired. Clay deposits are typically associated with very low energy depositional environments such as large lakes and marine basins.

Composition

Clay is composed primarily of fine-grained minerals, including kaolinite, montmorillonite, and other phyllosilicates, as well as quartz, feldspar, calcite, and gypsum. Clays are distinguished from other fine-grained soils by differences in size and mineralogy.

Formation

Clay minerals are typically formed over long periods of time by the gradual chemical weathering of rocks, usually silicate-bearing, by low concentrations of carbonic acid and other diluted solvents. These solvents, usually acidic, migrate through the weathering rock after leaching through upper weathered layers.

Uses

Clay is used in many industrial processes, such as paper making, cement production, and chemical filtering. Clay is also used in many kinds of building materials, such as bricks and tiles.

Health effects

Ingesting clay can have various effects on human health, depending on the type and quantity of clay ingested. Some types of clay are beneficial to human health, while others can be harmful.

See also

• Ceramics
• Pottery
• Sculpture
• Brick
• Tile

References

Clay Resources
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