shale -
A fine-grained sedimentary rock of a thin, laminated, and often friable, structure.
Verb
shale -
To take off the shell or coat of.
Wikipedia
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. 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.
