Dark grey Shale from the Jurassic of the Yorkshire coast. Originally deposited in a deep water marine environment. Occasionally fossiliferous.
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mixture of clay mineral flakes & tiny fragments (silt-sized particles) of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable.Shale is characterized by thin laminae or parallel layering or bedding less than one centimeter in thickness, making the rock fissile. Shales are associated with quiet water deposition such as in lakes, lagoons, deltas. In the case of this particular example from the Jurassic formations of the Yorkshire coast, the depositional environment was deep water marine. Specimens are supplied in a labelled card tray.