In Brief

Shale

Image courtesy of Daniel A. Vellone, Northeast Regional Geologist, USDA Natural Resources Conservation Service.

Shale is a sedimentary rock derived from mud and is commonly finely laminated (bedded). Particles in shale are commonly clay minerals mixed with tiny grains of quartz eroded from pre-existing rocks. Shaley means like a shale or having some shale component, as in shaley sandstone.