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