Know all about Slate and Marl properties here. All properties of rocks are important as they define the type of rock and its application. Slate belongs to Metamorphic Rocks while Marl belongs to Sedimentary Rocks.Texture of Slate is Foliated whereas that of Marl is Earthy. Slate appears Dull and Marl appears Rough and Dull. The luster of Slate and Marl is dull. Slate is available in black, brown, buff, green, light to dark grey, purple, red, shades of blue colors whereas Marl is available in beige, brown, green, grey, white colors. The commercial uses of Slate are blackboards, commemorative tablets, laboratory bench tops, standard material for the bed of billiard table, standard material for the beds of pool and snooker table, tombstones, used in aquariums, writing slates and that of Marl are creating artwork, soil conditioner.