+Shale is a fine-grained, layered [sedimentary rock](/wiki/sedimentary_rock) formed from compacted mud. Often dark and fragile, it can hold ancient organic matter, a source of [hydrocarbons](/wiki/hydrocarbon).
+## See also
+- [Oil Shale](/wiki/oil_shale)
+- [Natural Gas](/wiki/natural_gas)
+- [Rock](/wiki/rock)
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