Know all about Obsidian and Argillite properties here. All properties of rocks are important as they define the type of rock and its application. Obsidian belongs to Igneous Rocks while Argillite belongs to Sedimentary Rocks.Texture of Obsidian is Glassy whereas that of Argillite is Clastic, Polished. Obsidian appears Shiny and Argillite appears Rough and Dull. The luster of Obsidian is vitreous while that of Argillite is waxy and dull. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas Argillite is available in dark grey to black, pink, red, white colors. The commercial uses of Obsidian are creating artwork, mirror, used in aquariums and that of Argillite are fire resistant, used to manufracture paperweights and bookends.