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