noun \ˈshāl\

: a soft kind of rock that splits easily into flat pieces

Full Definition of SHALE

:  a fissile rock that is formed by the consolidation of clay, mud, or silt, has a finely stratified or laminated structure, and is composed of minerals essentially unaltered since deposition
shal·ey also shaly \ˈshā-lē\ adjective

Origin of SHALE

probably from obsolete or dialect shale scale, shell, from Middle English, from Old English scealu — more at shell
First Known Use: 1747


noun    (Concise Encyclopedia)

Any of a group of fine-grained, laminated sedimentary rocks consisting of silt- and clay-sized particles. Shale constitutes roughly 60% of the sedimentary rock in the Earth's crust. Shales are commercially important, particularly in the ceramics industry. They are a valuable raw material for tile, brick, and pottery and constitute a major source of alumina for portland cement. In addition, advances in recovery methods may one day make oil shale a practical source for liquid petroleum.


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