Characteristics related to grain size of rocks are called as texture. Here you can know more about texture of Gneiss and Obsidian. Texture of Gneiss is Banded, Foliated, Platy whereas that of Obsidian is Glassy. Based on the texture of rocks, they are used for various purposes. Get detailed information about Gneiss vs Obsidian texture, color, appearance and maintenance in the next section.