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