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Shale

A fissile rock composed of layers of claylike, fine-grained sediments.

A class of fine-grained clastic sedimentary rocks with a mean grain size of less than 0.0625 mm (0.0025 in.), including siltstone, mudstone, and claystone. One-half to two-thirds of all sedimentary rocks are shales.

Shales are usually classified or described according to the amount of silt, the presence and type of lamination, mineralogy, chemical composition, and color. Variations in these properties are related to the type of environment in which the shale was deposited and to postdepositional changes caused by diagenesis and compaction.

Shale comprises of clay as well as mud. It is distinguished by slender laminate infringement with an uneven curvature crack, often fragile and typically similar to the often-indistinguishable bedding flat surface. This property is known as the fissility. Shales are basically deposited in water that generally moves in a very slow movement. They are mostly noticeable in lake and lagoonal deposits, in river deltas, on floodplains and offshore of beach sands. They can also be deposited on the continental ledge, in comparatively deep, quiet water. Another type of shale is the Black shale. This formed due to the richness in unoxidized carbon. Shale’s that are subject matter to heat and force alter into a firm, fissile, and metamorphic substance recognized as slate, which is frequently used in building structure.

Shale is soft and porous. Colours in shale result from the presence of minerals and organic substances. For example, black shale results from organic matter, red shale from ferric iron, and green shale from ferric iron. Shale is of considerable economic value. Oil is extracted from shale in the united states, Brazil, and south Africa. Petroleum from this source can not be refined by the same methods used to refine crude oil. Shale in the eastern United States is a rich source of Uranium.

The most common sedimentary rock is shale. It is made of compressed mud--that is, a mixture of clay and silt (fine particles of mineral matter). Shale is used in making bricks.

Material Notes:
Sedimentary rock formed from clastic sediments.

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