Borolanite and Litchfieldite
Carbonate-rich Shale, Siliceous Shale and Cannel Shale
Application of acids on the surface causes cloudy frosting, Available in Lots of Colors and Patterns, Dissolves in hydrochloric acid, Is one of the oldest rock
Easily splits into thin plates, Generally rough to touch, Is one of the oldest rock, Very fine grained rock