Fire Clay

The earth here remembers the warmth of a sun long since vanished from these cursed skies.

Some portions of the Land of the Dead are comprised of patches of an exceptionally dense clay with some unique thermal properties. This clay is capable of retaining a great deal of heat, which is gradually but steadily released over long periods of time. Jars, pots, and other earthenware vessels comprised of fire clay are frequently used to keep things such as portions of food warm for extended periods of time, and a hearth lined with fire clay bricks can keep a room warm long after a fire has gone out
Some exposed patches of fire clay are still warm or even hot to the touch even Aeons after they had last been exposed to the absent sun, or some other great, ancient source of heat.

Type

Mineral