Earth Elemental

Elemental being made of stone, rock, sand, or any other material tied directly to the earth.
There are realms that consist primarily or exclusively of stone, and rocks, and the other materials that make up the ground beneath our feet. In these realms, only life that can exist must do so within the ground with no other means of sustenance. While there are an endless variety of such creatures, the majority of them have not been cataloged or named. These are known as earth elementals.
There are endless subgroups within the generic family of earth elemental. Stone elemental, sand elemental, mud elemental (from realms that also have water), and more. Earth elementals come in a variety of sizes, from a small rock to a mobile mountain. They come with a variety of abilities and powers, from simply being a piece of stone that can move on it's own to being a vaguely humanoid shape (or whatever is convenient) that can manipulate the world around them with but a thought.
While earth elementals originate strictly within realms of elemental earth, they occasionally travel, through one means or another, to other realms. Most often, this is by beings outside the elemental realms actively recruiting earth elementals via some means, whether magical or technological. Occasionally it is by spontaneous portals between realms opening and an elemental traveling through. On rare occasions, it is by the elemental itself having enough sentience, will, and power, to create a portal on its own. Most of the beings of the later category have been cataloged elsewhere.