Below is a guide on the Gather Material Stone task in Rune Factory 5.
Client: Darroch
Objective: Collect material stones
Rewards: Rock x4
After accepting the quest, Darroch will show up and give you a hammer. He’ll then ask that you collect some material stones. Head to the farm and smash the rocks in the field. Collect the material stones and place them in the stone and lumber container. Afterwards, return to the Task Board to complete the quest.