Brightstone is a type of mineral with unknown origins. It can be interacted with and shaped relatively easily, but is not brittle. When coming into contact with water, the stone begins to emit light. This is the primary source of light by the Imanity and Ghost's. It is unknown if it uses spiritual or magical energy to emit light.
Brightstone does not require to always remain in water, as long as contact is made for a brief period of time (depending on size) it will remain alight for a few minutes at a time. In Japanese it means Flourite. This was utilized by Riku and Aley when returning to base. Little else it known about it.
Brightstone torch commonly used for tunnels