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