The Inferno Gem

Enchanted Gem

A gem with the power to release a surge of flaming energy. Some can survive the heat. Others cannot.

It weighs about as much as an obsidian pebble the size of your palm, though the size is much smaller.

Created by magma, pressure, and a little bit of Infernus magic soaked into the soil, this gem was formed by 50 years of pressure as gravity sank it into the earth. The gravity has lightened and now the density is that of the obsidian listed above.

The particular gem featured in the series was finished forming that very year and started out as magma in the earth in the final year of AD.

Can give a person the power to conjure fire and be immortal to it, but there is a gene for it. If you don't have the gene, the stone will kill you upon contact, and if you have a bit of the gene, you are safe from the Inferno Rays but cannot wield the gem. If you are II (capital Inferno), then you can do both, and Infernuses are people solely bred to use the stone like a warrior. Infernuses have more divine power even than II humans and are therefore feared and in hiding.

@JuliusTan's notes on storybird.com about the Inferno Gem (artwork in Gallery by @JuliusTan):
Formed under pressure deep in the earth's crust, each of these magical stones have a unique incandescence that resembles a burning fire in them. The inferno stone is always warm to the touch, and no two stones are ever alike!