For years we assumed that our Shard, Autonomy, had Invested only Dayside, through the sunlight itself. We know now it is not as simple as this, though the mechanism is best explained under those assumptions. The Investiture beats down from the sky, and is absorbed by a microflora that grows like a lichen on the surface of the sand, giving it its brilliant white color (when fully Invested) or deep blackness (when that Investiture is depleted).
