Hellfire powder

Hellfire powder was a dangerous and volatile substance used to increase flames' temperature.

Description
This substance was a fine powder of reddish-orange hue, packed in pouches. When added to regular fire, hellfire powder dramatically increased its temperature. Because of that, hellfire powder was used by master smiths to melt and work such tough metals as adamantine. However, with usefulness came danger. Hellfire powder was an unstable substance that could become a fireball at any moment.

History
Hellfire powder retained its potency and properties for centuries, even if left untouched within ruins for many generations. The substance was in use in the forges of the ancient Imaskar. And by the late 14 century DR, hellfire powder was in use in Rashemen, the Sword Coast, and the nation of Samarach in Chult.