R672 Sample ID R672 • Cabinet C Chalk 9.195cm W x 13.872cm H x 5.85cm D • 594g Sample TypeRockRock QualitySedimentaryRock TypeOrganic CompositionCalaciteGrain SizeFineGrain ShapeRounded Grain SortingN/AAcid ReactionYesMohs Hardness 1 It is shaped like a medium sized rounded pebble. It has a hole in the shape. It is white and powders very easily, leaving white powder Description of Mohs scale here