From Grand Fantasia Wiki
Certain Mining class materials, such as ???, can only be obtained by building Reputation points with the Iron Stone Association. To do so, you will have to complete special repeatable quests that your Sprites may give you after a round of Mining. These look like yellow glowing scrolls, and after completing them, can be turned in to Iron Stone Association Cashier: Hatt in Jale. To complete them, you will simply need to collect whatever raw materials they require.