The moment Klaus' outstretched hand brushes the crystal, a burst of energy shoots into his body. It may be his imagination, but the crystals seem to actually grow to meet his touch. There is a light vibration in the cave walls, causing some loose rocks to fall. They roll directly to his feet. When he looks over, he sees that Estraeah has also went for one of the brown crystals.
Before he loses consciousness, he smells the faintest hint of rich soil, the kind you know will nourish any plant to its full potential. He does not feel himself hit the ground.