Know all about Marl and Obsidian properties here. All properties of rocks are important as they define the type of rock and its application. Marl belongs to Sedimentary Rocks while Obsidian belongs to Igneous Rocks.Texture of Marl is Earthy whereas that of Obsidian is Glassy. Marl appears Rough and Dull and Obsidian appears Shiny. The luster of Marl is dull while that of Obsidian is vitreous. Marl is available in beige, brown, green, grey, white colors whereas Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors. The commercial uses of Marl are creating artwork, soil conditioner and that of Obsidian are creating artwork, mirror, used in aquariums.