Faerie Stones

These are the shit. Everyone wants these. One of the most valuable materials on the planet.

These are small stones that gather and store magical energy, like a battery. They hold one spell slot, and recharge after a nights rest.

They come in Levels, 1-4, and hold one spell slot of that level. Sometimes they come in Flavors like Sparks, when they do, any spell cast with the stone that's the same Flavor, are cast at one slot higher. Ie, a lvl 1 Fire Faerie stone casts most spells as a 1st level slot, but casts any Fire spell as if you used a 2nd level slot.