From Destinypedia, the Destiny wiki
I examined the lattices myself. The crystals hold no natural attunement to any one fundamental force but, when exposed, achieve perfect fundamental force conduction.
She told me she got them from a trader at the Seven Stars, who got them from a Hunter, who got them from a Frame, who was programmed by a family in the Umbral District who had passed down the crystals as family heirlooms for generations, who'd been given the crystals by a Guardian back in the Dark Age in exchange for a home-cooked meal.
List of appearances