Fearglass

Fearglass is a black godglass that augments fear, driving its victim to running until the heart gives out and the mind breaks. Its effects are permanent and usually kills people, resulting in an empire-wide ban. It has little practical application beyond torture. Its fabrication is very difficult, reportedly driving many siliceers who tried to perfect the recipe insane, and notoriously dangerous to make.
STORY
When Filur Magna brings Thessa Foleer into Furnace Number Nine, she realizes he had been manufacturing illegal fearglass inside. When she refuses to tell him about the schematics he confiscated from her, Craftsman Magna burns Axio Darnasus with some molten fearglass. It tortures his mind with severe pain, driving him to tear at his own flesh to try and remove the fearglass from his skin. It eventually kills him.
Craftsman Magna also touches Demir Grappo with the molten fearglass, but it does not have the same effect since Demir had already suffered a severe mental anguish in his past at Holikan, which was worse, allowing him to maintain some of his faculties though the fearglass begins slowly killing him. To save his life, Thessa crafts a special piece of high-resonance braided godglass, infused with museglass, witglass, shackleglass, and cureglass to counteract the sorcery of the fearglass.

Type

Glass

Color

black