Carbon Stone

It is really terrible. The spore contamination of our water sources has become too serious. The water quality is still not good enough, even after filtering. Plus, we have almost run out of the  [Carbon Stones]  we need for filtering.
 * - ' [Avril] -- Quest Introductory Text: Filtering Carbon Stone

Source
Ore Stacks located within the Pioneers Mines.

Objective of Quests

 * Filtering Carbon Stone