Know all about Theralite and Tachylite properties here. All properties of rocks are important as they define the type of rock and its application. Theralite and Tachylite belong to Igneous Rocks.Texture of Theralite is Phaneritic whereas that of Tachylite is Vitreous. Theralite appears Veined and Shiny and Tachylite appears Glassy. The luster of Theralite is waxy and dull while that of Tachylite is resinous. Theralite is available in dark grey to black colors whereas Tachylite is available in black, dark brown colors. The commercial uses of Theralite and Tachylite are cemetery markers, commemorative tablets, creating artwork, laboratory bench tops, jewelry, sea defence, tombstones.