Fine soft rock, also known as Channel coal and jet, that splits easily and can be worked into ornaments and trinkets. In northern Europe during prehistoric times dark-colored black and grey shales were sought after and used for making pendants, rings, bracelets, etc. Sources include Kimmeridge, Dorset, and Whitby, North Yorkshire. Kimmeridge shale was also widely used in Romano-British times for ornaments and inlays.