Batteries to store magical energy, built out of iridium and flarestone.
Description
Iridium-Flarestone batteries, otherwise known as IF batteries, are batteries constructed out of iridium and flarestone with the purpose of storing magical energy.
Mechanics
Iridium cables lead magical (or electrical) energy into the flarestone, which absorbs the energy. This energy can later be somewhat safely harnessed by “rubbing” the flarestone using a precisely calibrated iridium plate.
Use
IF batteries are used in the largest cities of the world, to power the iridium network. Smaller variants (1-5kg) are often used to power magical artillery.
Misc
IF batteries are extremely volatile and sensitive to nearly all forms of energy, and so are kept under extremely tight, constant security underground. If a single 100kg IF battery cell were to be detonated, the blast would be able to entirely take out a small city with the force of half a ton of TNT.
The World Stones 