Know all about Obsidian and Tonalite properties here. All properties of rocks are important as they define the type of rock and its application. Obsidian and Tonalite belong to Igneous Rocks.Texture of Obsidian is Glassy whereas that of Tonalite is Phaneritic. Obsidian appears Shiny and Tonalite appears Banded and Foilated. The luster of Obsidian is vitreous while that of Tonalite is subvitreous to dull. Obsidian is available in black, blue, brown, green, orange, red, tan, yellow colors whereas Tonalite is available in black, brown, light to dark grey, white colors. The commercial uses of Obsidian are creating artwork, mirror, used in aquariums and that of Tonalite are cemetery markers, creating artwork.