R810 Sample ID R810 • Cabinet V Coal 26cm W x 25.5cm H x 6.838cm D • 8962g Sample TypeRockRock QualitySedimentaryRock TypeOrganic CompositionOrganicsGrain SizeMediumGrain ShapeN/A Grain SortingN/AAcid ReactionYesMohs Hardness 2 Its a big, dense rock that has layers. It contained a plant fossil that has been turned into coal. The rock is mostly brown in color with some black color where the plant fossil most likely was. Description of Mohs scale here