| Rock Name | Shale |
| Rock Class | Sedimentary |
| Class Characterisitcs | Clastic |
| Primary Building Blocks | Quartz, Clay Minerals |
+ HistoryShale 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 ApplicationsWithin 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. + Industrial ApplicationsShale 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. + EnvironmentShales 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. + MineralogyShales 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 HazardsNo known health risks have been associated with shale. However ingestion of shale, as with other naturally occurring rocks, is not recommended. + Mineral OnomasticsShale cannot be referenced in certain current and historical texts under any other name
+ References
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