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