A telluric planet (or terrestrial planet or rocky planet) is a planet mainly composed of sillicate rocks. They all share roughly the same structure: a central metallic core, mostly composed of iron, with a surrounding silicate mantle. The Moon is similar, but lacks an iron core. Telluric planets have canyons, craters, mountains, and volcanoes. The solar system includes four such planets, Mercury, Venus, the Earth and Mars; Ceres, despite its similarities to the aforementioned bodies, isn't considered a telluric planet, but rather a terrestrial dwarf planet. Pluto also bears similarities with telluric objects, but being composed mainly of icy material, it is rather considered an ice dwarf.