Fulgurite
Still crackling with the untamed fury of the storm that created it.
Thunderstorms are a common occurrence in the Land of the Dead, and lightning strikes happen with considerable frequency. Under the right conditions, the raw power and fury of an entire storm can, for a brief instant, become concentrated in a single lightning bolt that takes on a life of its own. When these discharges strike, they kick up a plume of superheated material from whatever surface they hit that melts and fuses together, fossilizing into what is known as a fulgurite. The fulgurites of the Land of the Dead are unlike the pillars of dirty fused sand and glass found in the realms of the living, instead still retaining a mere fraction of the storm's power within them that crackles and flickers across its surface.
Fulgurites can be dangerous. The raw power resonating within them has a habit of lashing out at any Soul that gets too close without being protected by the appropriate Wardings. Metallic objects, particularly those made of copper and silver, are especially attractive to the trapped lightning. Once a fulgurite has discharged its power in a dazzling, flashing arc of light and heat, it becomes dead and inert, little more than common glass and fused debris. It is said that there is an old Harpy known as the Storm Crone who is particularly skilled at working with fulgurites.
In some situations, a fulgurite can be host to a lost Soul and form a Kolossi.
Type
Glass
It's interesting to read about how fulgurite is different in the Land of the Dead. This feels very right for the material.