R751 Sample ID R751 • Cabinet C Limestone 9.518cm W x 9.645cm H x 5.618cm D • 996g Sample TypeRockRock QualitySedimentaryRock TypeChemical CompositionCalaciteGrain SizeFineGrain ShapeN/A Grain SortingWell sortedAcid ReactionYesMohs Hardness 4 The rock looks similar to a chunk of cheese. It is mostly white in color, with a bit of the top having some brown.. Description of Mohs scale here