The Stone Egg has three states, normal, overheated, and freezing. The Stone Egg grows while it is normal, and slowly shrinks when it is overheated or freezing. During the Night, the Egg will be freezing unless being placed close to a Fire, but during the Day, it will overheat if too close to a Fire. Unlike Hatching Tallbird Egg, it will never freeze or heat to death.
Despite being Eggs, The Stone Egg cannot be used in Crock Pot and has no Egg value.
Sneezing and dropping the Stone Egg will reset its progress.
An overheated Stone Egg.
A freezing Stone Egg.
A Stone Egg found at the BFB's nest.
An overheated Stone Egg after it's been placed by a Fire Pit.