The ability to use a crystal to create a magic item that is usable without attunement.
Idea for dwarven runeforged gear they take crystals and use a process to turn them into a powder(or other malleable form) and then add them to the metals during the forging process or use it to etch the runes into armor or weapons to bind certain magical effects. Different crystal types add different colored glow or other features to the gear.
Only a few different runes have been discovered for each type of crystal, making the set of possible magic items quite limited. Rumor has it there are dwarves that hold secret runes for themselves, and many scholars theorize that other runes may be possible.
