These stones are gifted by the cosmos and are often described as being fallen from the aether

Pixies are famously protective of their magic, but once a century, during the Zenith of the Blue Moon, a pixie may find a stone that resonates and calls from deep within their aetheric light. To imbue it, the pixie performs a ritual known as the Silver Sigh.

They breathe their own aetheric light, giving away one's life force, into the cracks of the stone. The stone stops being a mineral and becomes a vessel. This is why Pixie-Touched stones often seem to "choose" their owners by vibrating or changing temperature when held by the right person