Eskaphus

Name is eh at the moment. This stone is integral to several magic items. On its own, it's a powerful channel for magic, and a weak battery. With some refinement (a process that involves hellfire by necessity), it can be a very powerful battery that will last for a hundred years. With all the refinement, (A process that involves hellfire and Elemental Magic to manipulate the stone itself), the thing itself can generate a magical field with effects determined by the refining process.
Simple runes can be etched into the raw stone, but refined stone can't be carved into. Super-refined stone will usually develop etchings according to the way the magic set into it during the process.

The rock is plentiful enough basically everywhere you go. You have to dig a little harder for it in some than in others, but you're not going to have to travel far to find any. It forms in leylines along the planet and in one case, blew the fuck up during the Rising of the Forstford.

Ground into powder, it can be applied to surfaces, especially certain metal ones (I'll decide later), but the coating is known to weigh a lot.

It can be worked into metal but only at extremely high temperatures that even most smiths will need magic to achieve and contain/maintain. Most of the time the powdered form is poured over metal intended to receive enchantment, and then the piece is beaten out. The metal does lose a bit of strength, but magicking it back to full strength is totally doable and not even that hard for anyone of moderate skill.

It's metamorphous, but there's not really anyone that could tell you how it was formed. It appears in chunks and in veins, and it can be naturally alloyed (Sorry) with a lot of things.

Type

Ore/Mineral