Blastrock

Blastrock is a mineral found in Tortus.

Description
Blastrock is a combustible ore that when exposed to fire, it burns like oil. As it burns, it slowly decreases in volume until it eventually burns to cinders. Burning large quantities of blastrock in a confined space will make it explode violently. Depending on its quantity and pressure, it’s possible to create flames as strong as those created by fire magic.