Other uses are roofing, waterproofing, flooring for factories, and blending with rubber. Contact the Webmaster Shale Shale is the most abundant of all sedimentary rocks. It is composed primarily of soft clay minerals, but may include variable amounts of organic matter, calcareous material, and quartz grains. Shale may be any color, but is generally greenish gray to grayish black. It is relatively soft and has a smooth, greasy feel when freshly exposed, but is hard and brittle when dry.
Shales weather very easily to form mud and clay.
Numerous secondary minerals are associated with shales, including melanterite, copiapite, and halotrichite, which are described in Minerals . Shale, which crops out in southern Kentucky and around the Knobs area. It is brownish black, silty, pyritic, bituminous, and carbonaceous. The New Providence and Nancy Shales of Mississippian age, which also crop out in south-central Kentucky and around the Knobs area, are used in the brick industries of Kentucky. The most familiar characteristic of clay is plasticity or the ability of moist clay to be fashioned into a desired shape.