R753 Sample ID R753 • Cabinet C Black Shale 14.517cm W x 15.497cm H x 2.218cm D • 710g Sample TypeRockRock QualitySedimentaryRock TypeClastic CompositionClaysGrain SizeFineGrain ShapeAngular Grain SortingWell sortedAcid ReactionNoMohs Hardness 3 It is somewhat shaped like a right triangle with ripple marks on the top surface of the rock. It is greenish grey-brown in color. And the rock is thin in terms of thickness. Description of Mohs scale here