The xorn is a strange creature of elemental origin whose unlikely body can bring to mind a plant: six root-legs and a central trunk with three eyes, topped by a mighty maw. It famously feeds off gems, crystals, and precious stones, and can move through earth almost as smoothly as a fish through water.
Using its extraordinary sense of smell, the xorn can spot the crystals and gemstones it has a big appetite for. Even if the stones have been extracted or set in items, it can still sniff them out. A xorn who has not eaten in a long time can behave aggressively, bringing its many limbs to bear against anything wanting to deprive it of its meal.
Though a xorn digests crystallized mineral matter, its waste can be of great value to miners, as this elemental excretes chemically pure lumps: gold, silver, copper, mithral, sulfur, arsenic…
All the components mixed in minerals are sorted and compacted during their transit through the xorn's digestive tract. A true living ingot-casting machine! Such an anatomical peculiarity is a boon for miners, since it requires no fuel or chemicals. Provided one is willing to give up gemstones of any kind, one can get a lot out of a xorn. Thus, certain communities enslave xorns to exploit them. One must be careful, however, as the elemental can react violently when it panics or feels in danger.