Know all about Obsidian and Slate properties here. All properties of rocks are important as they define the type of rock and its application. Obsidian belongs to Igneous Rocks while Slate belongs to Metamorphic Rocks.Texture of Obsidian is Glassy whereas that of Slate is Foliated. Obsidian appears Shiny and Slate appears Dull. The luster of Obsidian is vitreous while that of Slate is dull. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas Slate is available in black, brown, buff, green, light to dark grey, purple, red, shades of blue colors. The commercial uses of Obsidian are creating artwork, mirror, used in aquariums and that 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.