Mól binding-crystals / elemental crystals

They are not gems and they are not mined. A Mól binding-crystal grows where the boundary between this world and another runs thin: crystallized essence of that other place, gathered at the seam, which is also why gates tend to open in such spots. Cut and primed by a Mól hand, one will hold a creature of the elements: air, fire, water, or the radiance that stands in for daylight far underground. Whether a given crystal already has something in it cannot be told by looking, and no way of asking has been found. They can be infused further with planar energy by a hand that knows how, and Nancáro has offered to do it.

Their use is to move and manage elementals, and to open doors. A tuned crystal serves as the key to a keep’s sealed doors, the keeps having been bound to one another by their making; the stones float in those halls because the site itself is a thin place, and a keyed crystal answers to the doorway rather than lying on a shelf like a rock. Beneath Haudh-Gwenn a single faceted crystal hung eight feet up in a chamber of screaming wind and drove it: blow, off, and suck, worked by a lever inside an ornate wheel. With the wind stopped the crystal loses its glow and can be handled freely. Shut the door and it re-primes itself to blowing, with a click a careful ear can catch first.

Crack one and what is inside comes out. Wanting a crystal to open the mountain keep’s sealed doors, Koa worked a fire crystal out of a lit brazier with tongs until it cracked, and the flame stood up as an elemental. His blade passed through it without touching it; he killed it by finding the glint inside the flame and shattering the crystal with the flat of his cutlass, and one fleck of dust was all that was ever found of it. An Elder of the keep remembered a crystal cracking and the ground itself rising up to rampage. Size and cut do the rest: a keep’s crystal must be large and fine enough to contain the keep’s magic, the element in it likely beside the point. To test whether a sodden patch of the eastern woods was a water-elemental epicenter, Mikhail floated a small, poorly cut water-stone into the heart of it, too far out to reach on a rope. It glowed, overcharged, and burst into a waterfall out of open sky.

The cutting was that keep’s own specialty. Its workshop still holds the magnifiers, the bins of chips and dust, the flawed small crystals and the tools, and the inscription over the well reads both ways at once: protect that which is within from without, protect that which is without from within, since what outsiders hungered for was the power and not the knowledge. The method survived the makers: schematics of Mól stone-cleaving were read out of a scroll case, and Yullen Gemsmith confirmed the reading almost to the word. Most stones carry impurities that bias them toward one element. A pure one carries none, and will take any. Hinta forges to suit, cutting a resting-slot into a blade for such a stone to sit in.