Slate is a fine-grained metamorphic rock with perfect cleavage that allows it to split into thin sheets. Slate usually has a light to dark brown streak. Slate is produced by low grade metamorphism, which is caused by relatively low temperatures and pressures. Marble is metamorphosed limestone or dolomite. Both limestone and dolomite have a large concentration of calcium carbonate . Marble has many different sizes of crystals. Marble has many color variances due to the impurities present at formation.