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