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