Rock Name Shale
Rock Class Sedimentary
Class Characterisitcs Clastic
Primary Building Blocks Quartz, Clay Minerals


+ History

Shale is a fine-grained, clastic sedimentary rock composed of mud. The mud itself is made up of flakes of clay minerals and tiny fragments of other minerals such as quartz and calcite. The process in the rock cycle which forms shale is compaction. The fine particles that compose shale can remain suspended in water long after the larger and denser particles of sand have deposited. The compaction process could have taken millions of years to complete. When analizing shale, the ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering or bedding less than one centimeter in thickness, called fissility. Mudstones, on the other hand, are similar in composition but do not show the fissility.

+ Metaphysical Applications

Within the metaphysical realm of rocks, shale aligns the Root chakra. shale can be used as a "worry stone" which, by rubbing the mineral, brings calm emotions. Use shale in breaking down defensive walls and to release old hurts and negative feelings which are no longer important. Shale can help in finding a way to respond positively to each new situation and works as an aid to change a person's “fight or flight”conditioned response, no matter how complex or difficult. Shale is also said to absorb negativity. Immensely useful in meditation and for shamanic journeying to the lower world.

Please note that MIROFOSS does not suggest in any way that minerals should be used in place of proper medical and psychological care. This information is provided here as a reference only.

+ Industrial Applications

Shale is used as filler in paint, plastic, roofing cement; as raw material for bricks; as landscaping and driveway material, and in some cases as a source of oil.

+ Environment

Shales are typically deposited in very slow moving water and are often found in lakes and lagoonal deposits, in river deltas, on floodplains and offshore from beach sands. They can also be deposited on the continental shelf, in relatively deep, quiet water.

+ Mineralogy

Shales are typically composed of variable amounts of clay minerals and quartz grains which cause the typical colour of shale to be gray. Addition of variable amounts of minor constituents alters the colour of the rock. Black shale results from the presence of greater than one percent carbonaceous material and indicates a reducing environment. Black shale can also be referred to as black metal. Red, brown and green colours are indicative of various minerals within the rock. Hematie causes the colour to turn red, goethite turns the rock various shades of brown and limonite causes the shale to turn yellow. Minerals in the mica group such as chlorites, biotite and illite will cause the shale to turn green. Shales that are subjected to heat and pressure of metamorphism alter into a hard, fissile, metamorphic rock known as slate. With continued increase in metamorphic grade the sequence is phyllite, then schist and finally to gneiss.

+ Health Hazards

No known health risks have been associated with shale. However ingestion of shale, as with other naturally occurring rocks, is not recommended.


+ Mineral Onomastics

Shale cannot be referenced in certain current and historical texts under any other name

The rock shale can be translated into the following select languages:

Arabic الطفل الصفحي Bulgarian шист Chinese (Sim) 页岩
Croatian škriljac Czech
Danish skifer
Dutch schalie Esperanto shale Estonian kilt
Finnish saviliuske French schiste argileux German schiefer
Greek σχιστόλιθος Hebrew פצל Hungarian agyagpala
Italian roccia scistosa Japanese 頁岩 Korean 혈암
Latin habeant Lithuanian skalūnas Norwegian shale
Persian شوره سر Polish łupek ilasty Portuguese xisto
Romanian shale Russian сланец Slovak škrupina
Spanish esquisto Swedish shale Tagalog pisara
Turkish şist Ukrainian сланець Vietnamese diệp thạch

+ References

Reference Blatt, Harvey and Robert J. Tracy, 1996, Petrology: Igneous, Sedimentary and Metamorphic, 2nd ed., Freeman, pp. 281–292 ISBN 0-7167-2438-3
Reference "Rocks: Materials of the Lithosphere – Summary". Retrieved 2007-07-31.
Reference Vine and E.B. Tourtelot (1970). "Geochemistry of black shale deposits – A summary report". Economic Geology 65: 253–273.
Reference R.M. Coveney, 2003, Metalliferous Paleozoic black shales and associated strata: in D.R. Lenz ed., Geochemistry of Sediments and Sedimentary Rocks, Geotext 4, Geological Association of Canada pp. 135–144
Reference H.D. Holland (1979). "Metals in black shales – A reassessment". Economic Geology 70: 1676–1680. doi:10.2113/gsecongeo.74.7.1676.
July 30, 2012 The last time this page was updated
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